Climbing Vibration-Driven Robot

ABSTRACT

An apparatus includes a housing, a rotational motor situated within the housing, a vibrating mechanism, and a plurality of appendages each having an appendage base proximal to the housing and an appendage tip distal from the housing. One or more of the appendages are adapted to cause the apparatus to move across a surface in a forward direction generally defined by a longitudinal offset between the appendage base and the appendage tip, and the appendages include two or more appendages disposed such that the appendage tips of the two or more appendages are adapted to contact opposing surfaces to produce a net force in a direction generally defined by a longitudinal offset between the appendage base and the appendage tip of the two or more appendages as the vibrating mechanism causes the apparatus to vibrate. The net force can allow the apparatus to climb when the opposing surfaces are inclined.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119 of ChinesePatent Application No. 201110461296.3, entitled “ClimbingVibration-Driven Robot,” filed Dec. 30, 2011, which is incorporatedherein by reference in its entirety.

BACKGROUND

This specification relates to devices that move based on oscillatorymotion and/or vibration.

One example of vibration driven movement is a vibrating electricfootball game. A vibrating horizontal metal surface induced inanimateplastic figures to move randomly or slightly directionally. More recentexamples of vibration driven motion use internal power sources and avibrating mechanism located on a vehicle.

One method of creating movement-inducing vibrations is to use rotationalmotors that spin a shaft attached to a counterweight. The rotation ofthe counterweight induces an oscillatory motion. Power sources includewind up springs that are manually powered or DC electric motors. Themost recent trend is to use pager motors designed to vibrate a pager orcell phone in silent mode. Vibrobots and Bristlebots are two modernexamples of vehicles that use vibration to induce movement. For example,small, robotic devices, such as Vibrobots and Bristlebots, can usemotors with counterweights to create vibrations. The robots' legs aregenerally metal wires or stiff plastic bristles. The vibration causesthe entire robot to vibrate up and down as well as rotate. These roboticdevices tend to drift and rotate because no significant directionalcontrol is achieved.

Vibrobots tend to use long metal wire legs. The shape and size of thesevehicles vary widely and typically range from short 2″ devices to tall10″ devices. Rubber feet are often added to the legs to avoid damagingtabletops and to alter the friction coefficient. Vibrobots typicallyhave 3 or 4 legs, although designs with 10-20 exist. The vibration ofthe body and legs creates a motion pattern that is mostly random indirection and in rotation. Collision with walls does not result in a newdirection and the result is that the wall only limits motion in thatdirection. The appearance of lifelike motion is very low due to thehighly random motion.

Bristlebots are sometimes described in the literature as tinydirectional Vibrobots. Bristlebots use hundreds of short nylon bristlesfor legs. The most common source of the bristles, and the vehicle body,is to use the entire head of a toothbrush. A pager motor and batterycomplete the typical design. Motion can be random and directionlessdepending on the motor and body orientation and bristle direction.Designs that use bristles angled to the rear with an attached rotatingmotor can achieve a general forward direction with varying amounts ofturning and sideways drifting. Collisions with objects such as wallscause the vehicle to stop, then turn left or right and continue on in ageneral forward direction. The appearance of lifelike motion is minimaldue to a gliding movement and a zombie-like reaction to hitting a wall.

SUMMARY

In general, one innovative aspect of the subject matter described inthis specification can be embodied in an apparatus that includes a body,a vibrating mechanism coupled to the body, and a plurality of appendageseach having an appendage base proximal to the body and an appendage tipdistal to the body. At least a portion of the plurality of appendagesare adapted to cause the apparatus to move across a surface in a forwarddirection generally defined by a longitudinal offset between theappendage base and the appendage tip as the vibrating mechanism causesthe apparatus to vibrate. In addition, the plurality of appendagesinclude two or more appendages disposed such that the appendage tips ofthe two or more appendages are adapted to contact opposing surfaces toproduce a net force in a direction generally defined by a longitudinaloffset between the appendage base and the appendage tip of the two ormore appendages as the vibrating mechanism causes the apparatus tovibrate.

These and other embodiments can each optionally include one or more ofthe following features. The opposing surfaces include at least twosurfaces. The opposing surfaces include opposing surfaces that aresubstantially parallel to one another. The at least two surfaces aredisposed on an at least substantially enclosed conduit. The net force ina direction generally defined by an offset between the appendage baseand the appendage tip of the two or more appendages exceeds an opposinggravitational force on the apparatus. The net force enables theapparatus to climb between substantially vertical opposing surfaces.Each of the two or more appendages, as a result of contact with acorresponding surface, produce a net force that includes a positivecomponent force in a direction substantially perpendicular to thecorresponding surface and a positive component force in a directiongenerally defined by a longitudinal offset between the appendage baseand the appendage tip. The positive component force in the directionsubstantially perpendicular to the corresponding surface for one of thetwo or more appendages is substantially opposed to the positivecomponent force in the direction substantially perpendicular to thecorresponding surface for at least one other appendage of the two ormore appendages. The plurality of appendages include a plurality of legsgenerally disposed in a first direction and the two or more appendagesinclude a first appendage generally disposed in a second directionsubstantially opposite the first direction. The two or more appendagesfurther include at least two legs of the plurality of legs, and the atleast two legs and the first appendage are adapted to enable theapparatus to climb between substantially vertical surfaces that arespaced such that the appendage tips of the at least two legs and theappendage tip the first appendage apply alternating forces on theopposing surfaces. The legs are arranged in two rows, with the appendagebase of the legs in each row coupled to the body substantially along alateral edge of the body. The body includes a housing, a rotationalmotor is situated within the housing, the legs are integrally coupled toa portion of the housing at a leg base, and at least a portion of thehousing is situated between the two rows of legs. At least one of thetwo or more appendages is removably attached to the body. The pluralityof appendages include a plurality of legs generally disposed in a firstdirection and the two or more appendages include: a first appendagegenerally disposed in a second direction substantially perpendicular tothe first direction; and a second appendage generally disposed in athird direction substantially perpendicular to the first direction andsubstantially opposite the second direction. The vibrating mechanismincludes a rotational motor that rotates an eccentric load. Theplurality of appendages include a plurality of legs generally disposedin a first direction, the rotational motor has an axis of rotation thatpasses within about 20% of the center of gravity of the apparatus as apercentage of the height of the apparatus, and the housing is configuredto facilitate rolling of the apparatus about a longitudinal center ofgravity of the apparatus, based on a rotation of the eccentric load,with the apparatus on a substantially flat surface when the legs are notoriented such that a leg tip of at least one leg on each lateral side ofthe body contacts a substantially level surface. The plurality of legsare arranged in two rows and the rows are substantially parallel to theaxis of rotation of the rotational motor, and at least some of the legtips that contact the substantially flat surface tend to substantiallyprevent rolling of the apparatus based on a spacing of the two rows oflegs when the legs are oriented such that a leg tip of at least one legon each lateral side of the body contacts the substantially flatsurface. At least one of the two or more appendages are forward of alongitudinal center of gravity of the apparatus. Each of the pluralityof appendages are constructed from a flexible material, injectionmolded, and integrally coupled to the body at the appendage base. Forcesfrom rotation of the eccentric load interact with a resilientcharacteristic of at least one driving appendage to cause the at leastone driving appendage to leave a support surface as the apparatustranslates in the forward direction. A coefficient of friction of aportion of at least a subset of the legs that contact a support surfaceis sufficient to substantially eliminate drifting in a lateraldirection. The eccentric load is configured to be located toward a frontend of the apparatus relative to driving appendages, and the front endof the apparatus is defined by an end in a direction that the apparatusprimarily tends to move as the rotational motor rotates the eccentricload. The plurality of appendages are integrally molded with at least aportion of the body. At least a subset of the plurality of appendages,including the two or more appendages, are curved, and a ratio of aradius of curvature of the curved appendages to appendage length of theappendages is in a range of 2.5 to 20.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in methods that include the actionsof inducing vibration of a vibration-driven device, and causing thedevice to climb a substantially inclined, and at least partiallyenclosed, conduit using two or more appendages that deflect to allowmovement of the device in the forward direction and that provideresistance to movement in a backward direction that is opposite theforward direction. The vibration-driven device includes a body and aplurality of molded legs each having a leg base and a leg tip at adistal end relative to the leg base. The legs are coupled to the body atthe leg base and include at least one elastomeric driving leg, andvibration causes the device to move in a forward direction generallydefined by an offset between the leg base and the leg tip of the atleast one driving leg as the device vibrates. The two or more appendagesfurther provide substantially opposing forces on the device, with eachopposing force being in a direction substantially orthogonal to theforward direction.

These and other embodiments can each optionally include one or more ofthe following features. The device is supported on a surface, and thedevice is induced or otherwise caused to move across the surface in theforward direction generally defined by an offset between the leg baseand the leg tip of the at least one driving leg as the device vibrates.Vibration of the device causes the at least one driving leg to deflectin a direction opposite the forward direction without substantialslipping of the at least one driving leg on the surface when net forceson the at least one driving leg are downward, and resiliency of the atleast one elastomeric driving leg causes the at least one driving leg todeflect in the forward direction when net forces on the at least onedriving leg are upward. Inducing vibration includes rotating aneccentric load. The two or more appendages are attached to the body ofthe device. At least one of the two or more appendages comprises one ofthe plurality of legs and at least one of the two or more appendages isattached to a top side of the body. The two or more appendages areattached to the conduit and contact the body of the device. The two ormore appendages include at least three appendages. The two or moreappendages are adapted to allow the device to climb a vertical conduit.The two or more appendages are attached to the device body, and theconduit, the device body, and the two or more appendages are configuredsuch that each of the two or more appendages are repeatedly in contactwith an internal surface of the conduit for sufficient periods toproduce generally forward motion. Vibration of the device causes atleast one of the two or more appendages to deflect in a directionopposite the forward direction without substantial slipping of the atleast one appendage on a corresponding internal surface of the conduitwhen net forces on the at least one appendage are toward thecorresponding internal surface, and resiliency of the at least oneappendage causes the at least one appendage to deflect in the forwarddirection when net forces on the at least one appendage are away fromthe corresponding internal surface.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in an apparatus including a body, avibrating mechanism coupled to the body, and a plurality of appendageseach having an appendage base proximal to the body and an appendage tipdistal to the body. At least a subset of the plurality of appendagesextend from the body, are disposed such that each of the appendages inthe subset contact one of a plurality of substantially parallelsurfaces, and are adapted to cause the apparatus to climb up asubstantially inclined surface as vibration induced by the vibratingmechanism causes the appendages in the subset to at least alternatelycontact one of the plurality of substantially parallel surfaces.

These and other embodiments can each optionally include one or more ofthe following features. Vibration induced by the vibrating mechanismcauses at least one of the appendages in the subset to maintain at leastsubstantially constant contact with one of the plurality ofsubstantially parallel surfaces and at least one of the appendages inthe subset to alternately contact and leave an opposing surface of theplurality of substantially parallel surfaces. At least one of theappendages in the subset maintains at least substantially constantcontact with one of the plurality of substantially parallel surfaces andat least one of the appendages in the subset maintains substantiallyconstant contact with an opposing surface of the plurality ofsubstantially parallel surfaces. Contact by each of at least two of theappendages in the subset with a corresponding one of the plurality ofsurfaces provides substantially opposing forces that facilitate climbingof the substantially inclined surface by the apparatus. The subset ofthe plurality of appendages are adapted to produce a force in a forwarddirection generally defined by a longitudinal offset between anappendage base proximal to the body and an appendage tip distal from thebody as the vibrating mechanism causes the appendages to substantiallymaintain constant contact with the two alternately contact one of theplurality of parallel surfaces. Each of the appendages in the subset arecurved in a direction substantially opposite the forward direction andconstructed from an elastomeric material.

In general, one innovative aspect of the subject matter described inthis specification can be embodied in a system including an inclinedconduit having two substantially parallel opposing surfaces, anautonomous device including a body, a vibrating mechanism coupled to thebody, and a plurality of appendages each having an appendage baseproximal to the body and an appendage tip distal to the body. At least aportion of the plurality of appendages are adapted to cause theapparatus to move across a surface in a forward direction generallydefined by a longitudinal offset between the appendage base and theappendage tip as the vibrating mechanism causes the apparatus tovibrate. The plurality of appendages include two or more appendagesdisposed such that the appendage tips of the two or more appendages areadapted to contact the two substantially parallel opposing surfaces toproduce a net force in a direction generally defined by a longitudinaloffset between the appendage base and the appendage tip of the two ormore appendages as the vibrating mechanism causes the apparatus tovibrate. The net force causes the autonomous device to climb theinclined conduit.

These and other embodiments can each optionally include one or more ofthe following features. The conduit comprises a tube. The conduit has awidth sufficient to allow two of the autonomous devices to pass oneanother. The conduct includes at least one of a straight component, acurved component, an intersection component, or a connector. A pluralityof conduit components are adapted to connect together to create ahabitat.

The details of one or more embodiments of the subject matter describedin this specification are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages of thesubject matter will become apparent from the description, the drawings,and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram that illustrates an example vibration powereddevice.

FIGS. 2A, 2B, 3A, and 3B are diagrams that illustrate example forcesthat are involved with movement of the vibration powered device of FIG.1.

FIG. 4 shows an example front view indicating a center of gravity forthe device.

FIG. 5 shows an example side view indicating a center of gravity for thedevice.

FIG. 6 shows an example device that includes a pair of sideclimber-appendages.

FIGS. 7A and 7B show example dimensions of the device.

FIGS. 7C and 7D collectively show an example of a removably attachableappendage for the device.

FIGS. 7E and 7F show another example of a removably attachable appendagefor the device.

FIG. 8 shows one example configuration of example materials from whichthe device can be constructed.

FIG. 9A shows an example environment in which the device can operate andclimb inside a conduit.

FIG. 9B shows the example environment in which the device has climbedinside of and nearly to the top of the conduit.

FIG. 9C shows an example loop conduit in the shape of a double loop.

FIG. 9D is a diagram of a conduit adapted to facilitate climbing by avibration-powered device.

FIG. 10A is a flow diagram of a process for operating avibration-powered device.

FIG. 10B is a flow diagram of a process for the vibration-powered deviceto climb.

FIG. 11 is a flow diagram of a process for constructing avibration-powered device.

FIG. 12A shows an example tube habitat in which multiple devices canoperate and interact.

FIG. 12B shows a top view of the tube habitat.

FIGS. 13A through 13D show various views of an example straight tubeassembly.

FIGS. 13E through 13G show example dimensions of the straight tubeassembly.

FIGS. 13H through 13K show various views of an example curved tubeassembly.

FIGS. 13L through 13Q show various views of an example Y-shaped tubeassembly.

FIGS. 13R through 13W show various views of an example loop tubeassembly.

FIGS. 14A through 14D show various views of an example connector.

FIGS. 14E through 14H show various views of another example connector.

FIG. 15A is a side view of the alternative vibration powered device.

FIG. 15B is a top view of the alternative vibration powered device.

FIG. 15C is a front view of the alternative vibration powered device.

FIG. 15D is a side view of the alternative vibration powered device asit moves through an example upwardly curved conduit.

Like reference numbers and designations in the various drawings indicatelike elements.

DETAILED DESCRIPTION

Small robotic devices, or vibration-powered vehicles, can be designed tomove across a surface, e.g., a floor, table, other relatively flat orsmooth surface, or a concave or convex (e.g., in any direction) curvedsurface. The robotic device is adapted to move autonomously and, in someimplementations, turn in seemingly random directions. In general, therobotic devices include a body (or housing), multiple appendages (e.g.,legs and other appendages), and a vibrating mechanism (e.g., a motor orspring-loaded mechanical winding mechanism rotating an eccentric load, amotor or other mechanism adapted to induce oscillation of acounterweight, or other arrangement of components adapted to rapidlyalter the center of mass of the device). As a result, the miniaturerobotic devices, when in motion, can resemble organic life, such as bugsor insects.

Movement of the robotic device can be induced by the motion of arotational motor inside of, or attached to, the device, in combinationwith a rotating weight with a center of mass that is offset relative tothe rotational axis of the motor. The rotational movement of the weightcauses the motor and the robotic device to which it is attached tovibrate. In some implementations, the rotation is approximately in therange of 6000-9000 revolutions per minute (rpm's), although higher orlower rpm values can be used. As an example, the device can use the typeof vibration mechanism that exists in many pagers and cell phones that,when in vibrate mode, cause the pager or cell phone to vibrate. Thevibration induced by the vibration mechanism can cause the device tomove across the surface (e.g., the floor), e.g., using legs that areconfigured to alternately flex (in a particular direction) and return tothe original position as the vibration causes the device to move up anddown.

Various features can be incorporated into the robotic devices. Forexample, various implementations of the devices can include variationsof certain features, e.g., the shape of the legs and/or otherappendages, the number of legs and/or other appendages, the frictionalcharacteristics of the leg and/or other appendage tips, the relativestiffness or flexibility of the legs and/or other appendages, theresiliency of the legs and/or other appendages, the relative location ofthe rotating counterweight with respect to the legs and/or otherappendages/legs, etc. For example, the variations of certain featurescan facilitate efficient transfer of vibrations to forward motion,including forward motion that can enable the device to climb at anyangle and any orientation including right-side-up, up-side-down, andsideways orientation. The speed and direction of the robotic device'smovement can depend on many factors, including the rotational speed ofthe motor, the size of the offset weight attached to the motor, thepower supply, the characteristics (e.g., size, orientation, shape,material, resiliency, frictional characteristics, etc.) of theappendages attached to the housing of the device, the properties of thesurface on which the device operates, the overall weight of the device,and so on. While in general, appendages include legs upon which thedevice rests on a substantially flat surface and by which forward motionon the surface is achieved, the appendages can also include non-legappendages (e.g., on the top or sides of the device) that provide othermovement capabilities for the device, such as the ability of the deviceto climb, as will be described below.

In some implementations, the devices include features that are designedto compensate for a tendency of the device to turn as a result of therotation of the counterweight and/or to alter the tendency for, anddirection of, turning between different robotic devices. The componentsof the device can be positioned to maintain a relatively low center ofgravity (or center of mass) to discourage tipping (e.g., based on thelateral distance between the leg tips) and to align the components withthe rotational axis of the rotating motor to encourage rolling (e.g.,when the device is not upright). Likewise, the device can be designed toencourage self-righting based on features that tend to encourage rollingwhen the device is on its back or side in combination with the relativeflatness of the device when it is upright (e.g., when the device is“standing” on its leg tips). Features of the device can also be used toincrease the appearance of random motion and to make the device appearto respond intelligently to obstacles. Different leg configurations andplacements can also induce different types of motion and/or differentresponses to vibration, obstacles, or other forces. Moreover, adjustableleg lengths can be used to provide some degree of steering capability.In some implementations, the robotic devices can simulate real-lifeobjects, such as crawling bugs, rodents, or other animals and insects.

FIG. 1 is a diagram that illustrates an example vibration powered device100 that is shaped like a bug. The device 100 includes a body (e.g., ahousing 102, resembling the body of the bug) and appendages (e.g., legs104). Inside (or attached to) the housing 102 are the components thatcontrol and provide movement for the device 100, including a rotationalmotor, power supply (e.g., a battery), and an on/off switch. Each of theappendages (e.g., legs 104) includes an appendage tip (e.g., a leg tip106 a) and an appendage base (e.g., a leg base 106 b). Appendage basesare proximal to the body, and appendage tips are distal from the body.The properties of the appendages (e.g., the legs 104), including theposition of each appendage base (e.g., the leg base 106 b) relative tothe appendage tip (e.g., the leg tip 106 a), can contribute to thedirection and speed in which the device 100 tends to move. For example,each appendage base is located farther forward than the tip, and thisconfiguration allows the device 100 to move generally in the forwarddirection. The device 100 is depicted in an upright position (i.e.,standing on the legs 104) on a supporting surface 110 (e.g., asubstantially planar floor, table top, etc. that counteractsgravitational forces).

As shown in FIG. 1, the housing 102 includes at least a front 111 a, aback 111 b, lateral sides, a top, and a bottom. The device 100 tends tomove toward the front 111 a of the device 100 based on the configurationof the appendages. The plurality of appendages includes a plurality oflegs 104 that are generally disposed in a first direction (e.g.,extending substantially downward from the bottom of the housing 102).The plurality of appendages also include one or more other non-legappendages generally disposed in at least a second direction (e.g.,extending substantially upward from the top of the housing 102, outwardfrom the side of the housing 102, or some combination thereof). In someimplementations, the first and second directions are substantiallyopposite each other, while, in other implementations, the non-legappendages can substantially oppose one another or, in combination,provide a force that is in substantial opposition to the plurality oflegs 104 when the non-leg appendages are in contact with a surface.

For example, the non-leg appendages also include one or moreclimber-appendages (e.g., a top climber-appendage 105) that are disposedin directions opposite the legs 104. For example, unlike the legs 104that point generally downward from the housing 102 (e.g., toward thesurface 110), the top climber-appendage 105 points generally upward. Asshown in FIG. 1, the top climber-appendage 105 may be shorter than thelength of the legs 104, but long enough to project higher than thehighest point on the housing 102. Further, the top climber-appendage 105can project a little farther from the center of gravity of the housing102 than, a little less than, or about the same as the distance that thelegs 104 project below the center of gravity of the housing 102. Asshown, the top climber-appendage 105 can have roughly the same curvatureand slope as the legs 104, and the top climber-appendage 105 can beplaced such that the appendage tip of the top climber-appendage 105 isnear the leg tips of front legs 104 a, e.g., in the longitudinal traveldirection of the device. Other implementations are possible. Forexample, the top climber-appendage 105 can be further forward or back ofthe housing 102. In another example, the top climber-appendage 105 canhave a different shape (e.g., including the curvature of the appendage)and size. In some implementations, multiple top climber-appendages 105can exist, such as in rows and/or columns relative to the forwarddirection of the device 100.

Overview of Legs

Legs 104 can include front legs 104 a, middle legs 104 b, and rear legs104 c. For example, the device 100 can include a pair of front legs 104a that may be designed to perform differently from middle legs 104 b andrear legs 104 c. For example, the front legs 104 a may be configured toprovide a driving force for the device 100 by contacting an underlyingsurface 110 and causing the device to hop forward as the devicevibrates. Middle legs 104 b can help provide support to counteractmaterial fatigue (e.g., after the device 100 rests on the legs 104 forlong periods of time) that may eventually cause the front legs 104 a todeform and/or lose resiliency. In some implementations, device 100 canexclude middle legs 104 b and include only front legs 104 a and rearlegs 104 c. In some implementations, front legs 104 a and one or morerear legs 104 c can be designed to be in contact with a surface, whilemiddle legs 104 b can be slightly off the surface so that the middlelegs 104 b do not introduce significant additional drag forces and/orhopping forces that may make it more difficult to achieve desiredmovements (e.g., tendency to move in a relatively straight line and/or adesired amount of randomness of motion).

In some implementations, the device 100 can be configured such that onlytwo front legs 104 a and one rear leg 104 c are in contact with asubstantially flat surface 110, even if the device includes more thanone rear leg 104 c and several middle legs 104 b. In otherimplementations, the device 100 can be configured such that only onefront leg 104 a and two rear legs 104 c are in contact with a flatsurface 110. Throughout this specification, descriptions of being incontact with the surface can include a relative degree of contact. Forexample, when one or more of the front legs 104 a and one or more of theback legs 104 c are described as being in contact with a substantiallyflat surface 110 and the middle legs 104 b are described as not being incontact with the surface 110, it is also possible that the front andback legs 104 a and 104 c can simply be sufficiently longer than themiddle legs 104 b (and sufficiently stiff) that the front and back legs104 a and 104 c provide more support for the weight of the device 100than do the middle legs 104 b, even though the middle legs 104 b aretechnically actually in contact with the surface 110. In someimplementations, even legs that have a lesser contribution to support ofthe device may nonetheless be in contact when the device 100 is in anupright position, especially when vibration of the device causes an upand down movement that compresses and bends the driving legs and allowsadditional legs to contact the surface 110. Greater predictability andcontrol of movement (e.g., in a straight direction) can be obtained byconstructing the device so that a sufficiently small number of legs(e.g., fewer than twenty or fewer than thirty) contact the supportsurface 110 and/or contribute to the support of the device in theupright position when the device is either at rest or as the rotatingeccentric load induces movement. In this respect, it is possible forsome legs to provide support even without contacting the support surface110 (e.g., one or more short legs can provide stability by contacting anadjacent longer leg to increase overall stiffness of the adjacent longerleg). Typically, however, each leg is sufficiently stiff that four orfewer legs are capable of supporting the weight of the device withoutsubstantial deformation (e.g., less than 5% as a percentage of theheight of the leg base 106 b from the support surface 110 when thedevice 100 is in an upright position).

Different leg lengths can be used to introduce different movementcharacteristics, as further discussed below. The various legs can alsoinclude different properties, e.g., different stiffnesses orcoefficients of friction, as further described below. Generally, thelegs can be arranged in substantially parallel rows along each lateralside of the device 100 (e.g., FIG. 1 depicts one row of legs on theright lateral side of the device 100; a corresponding row of legs (notshown in FIG. 1) can be situated along the left lateral side of thedevice 100).

In general, the number of legs 104 that provide meaningful or anysupport for the device can be relatively limited. For example, the useof less than twenty legs that contact the support surface 110 and/orthat provide support for the device 100 when the device 100 is in anupright position (i.e., an orientation in which the one or more drivinglegs 104 a are in contact with a support surface) can provide morepredictability in the directional movement tendencies of the device 100(e.g., a tendency to move in a relatively straight and forwarddirection), or can enhance a tendency to move relatively fast byincreasing the potential deflection of a smaller number of legs, or canminimize the number of legs that may need to be altered to achieve thedesired directional control, or can improve the manufacturability offewer legs with sufficient spacing to allow room for tooling. Inaddition to providing support by contacting the support surface 110,legs 104 can provide support by, for example, providing increasedstability for legs that contact the surface 110. In someimplementations, each of the legs that provides independent support forthe device 100 is capable of supporting a substantial portion of theweight of the device 100. For example, the legs 104 can be sufficientlystiff that four or fewer legs are capable of statically (e.g., when thedevice is at rest) supporting the device without substantial deformationof the legs 104 (e.g., without causing the legs to deform such that thebody of the device 100 moves more than 5% as a percentage of the heightof the leg base 106 b from the support surface).

As described here at a high level, many factors or features cancontribute to the movement and control of the device 100. For example,the device's center of gravity (CG), and whether it is more forward ortowards the rear of the device, can influence the tendency of the device100 to turn. Moreover, a lower CG can help to prevent the device 100from tipping over. The location and distribution of the legs 104relative to the CG can also prevent tipping. For example, if pairs orrows of legs 104 on each side of the device 100 are too close togetherand the device 100 has a relatively high CG (e.g., relative to thelateral distance between the rows or pairs of legs), then the device 100may have a tendency to tip over on its side. Thus, in someimplementations, the device includes rows or pairs of legs 104 thatprovide a wider lateral stance (e.g., pairs of front legs 104 a, middlelegs 104 b, and rear legs 104 c are spaced apart by a distance thatdefines an approximate width of the lateral stance) than a distancebetween the CG and a flat supporting surface on which the device 100rests in an upright position. For example, the distance between the CGand the supporting surface can be in the range of 50-80% of the value ofthe lateral stance (e.g., if the lateral stance is 0.5 inches, the CGmay be in the range of 0.25-0.4 inches from the surface 110). Moreover,the vertical location of the CG of the device 100 can be within a rangeof 40-60% of the distance between a plane that passes through the legtips 106 a and the highest protruding surface on the top side of thehousing 102. In some implementations, a distance 409 a and 409 b (asshown in FIG. 4) between each row of the tips of legs 104 and alongitudinal axis of the device 100 that runs through the CG can beroughly the same or less than the distance 406 (as shown in FIG. 4)between the tips 106 a of two rows of legs 104 to help facilitatestability when the device is resting on both rows of legs.

The device 100 can also include features that generally compensate forthe device's tendency to turn. Driving legs (e.g., front legs 104 a) canbe configured such that one or more legs on one lateral side of thedevice 100 can provide a greater driving force than one or morecorresponding legs on the other lateral side of the device 100 (e.g.,through relative leg lengths, relative stiffness or resiliency, relativefore/aft location in the longitudinal direction, or relative lateraldistance from the CG). Similarly, dragging legs (e.g., back legs 104 c)can be configured such that one or more legs on one lateral side of thedevice 100 can provide a greater drag force than one or morecorresponding legs on the other lateral side of the device 100 (e.g.,through relative leg lengths, relative stiffness or resiliency, relativefore/aft location in the longitudinal direction, or relative lateraldistance from the CG). In some implementations, the leg lengths can betuned either during manufacturing or subsequently to modify (e.g.,increase or reduce) a tendency of the device to turn.

Movement of the device can also be influenced by the leg geometry of thelegs 104. For example, a longitudinal offset between the leg tip (i.e.,the end of the leg that touches the surface 110) and the leg base (i.e.,the end of the leg that attaches to the device housing) of any drivinglegs induces movement in a forward direction as the device vibrates.Including some curvature, at least in the driving legs, furtherfacilitates forward motion as the legs tend to bend, moving the deviceforward, when vibrations force the device downward and then spring backto a straighter configuration as the vibrations force the device upward(e.g., resulting in hopping completely or partially off the surface,such that the leg tips move forward above or slide forward across thesurface 110).

The ability of the legs to induce forward motion results in part fromthe ability of the device to vibrate vertically on the resilient legs.As shown in FIG. 1, the device 100 includes an underside 122. The powersupply and motor for the device 100 can be contained in a chamber thatis formed between the underside 122 and the upper body of the device,for example. The length of the legs 104 creates a space 124 (at least inthe vicinity of the driving legs) between the underside 122 and thesurface 110 on which the device 100 operates. The size of the space 124depends on how far the legs 104 extend below the device relative to theunderside 122. The space 124 provides room for the device 100 (at leastin the vicinity of the driving legs) to move downward as the periodicdownward force resulting from the rotation of the eccentric load causesthe legs to bend. This downward movement can facilitate forward motioninduced by the bending of the legs 104.

The device can also include the ability to self-right itself, forexample, if the device 100 tips over or is placed on its side or back.For example, constructing the device 100 such that the rotational axisof the motor and the eccentric load are approximately aligned with thelongitudinal CG of the device 100 tends to enhance the tendency of thedevice 100 to roll (i.e., in a direction opposite the rotation of themotor and the eccentric load). Moreover, construction of the devicehousing to prevent the device from resting on its top or side (e.g.,using one or more protrusions on the top and/or sides of the devicehousing) and to increase the tendency of the device to bounce when onits top or side can enhance the tendency to roll. Furthermore,constructing the legs of a sufficiently flexible material and providingclearance on the housing undercarriage that the leg tips to bend inwardcan help facilitate rolling of the device from its side to an uprightposition.

FIG. 1 shows a body shoulder 112 and a head side surface 114, which canbe constructed from rubber, elastomer, or other resilient material,contributing to the device's ability to self-right after tipping. Thebounce from the shoulder 112 and the head side surface 114 can besignificantly more than the lateral bounce achieved from the legs, whichcan be made of rubber or some other elastomeric material, but which canbe less resilient than the shoulder 112 and the head side surface 114(e.g., due to the relative lateral stiffness of the shoulder 112 and thehead side surface 114 compared to the legs 104). Rubber legs 104, whichcan bend inward toward the body 102 as the device 100 rolls, increasethe self-righting tendency, especially when combined with theangular/rolling forces induced by rotation of the eccentric load. Thebounce from the shoulder 112 and the head side surface 114 can alsoallow the device 100 to become sufficiently airborne that the angularforces induced by rotation of the eccentric load can cause the device toroll, thereby facilitating self-righting.

The device can also be configured to include a degree of randomness ofmotion, which can make the device 100 appear to behave like an insect orother animate object. For example, vibration induced by rotation of theeccentric load can further induce hopping as a result of the curvatureand “tilt” of the legs. The hopping can further induce a verticalacceleration (e.g., away from the surface 110) and a forwardacceleration (e.g., generally toward the direction of forward movementof the device 100). During each hop, the rotation of the eccentric loadcan further cause the device to turn toward one side or the otherdepending on the location and direction of movement of the eccentricload. The degree of random motion can be increased if relatively stifferlegs are used to increase the amplitude of hopping. The degree of randommotion can be influenced by the degree to which the rotation of theeccentric load tends to be either in phase or out of phase with thehopping of the device (e.g., out of phase rotation relative to hoppingmay increase the randomness of motion). The degree of random motion canalso be influenced by the degree to which the back legs 104 c tend todrag. For example, dragging of back legs 104 c on both lateral sides ofthe device 100 may tend to keep the device 100 traveling in a morestraight line, while back legs 104 c that tend to not drag (e.g., if thelegs bounce completely off the ground) or dragging of back legs 104 cmore on one side of the device 100 than the other can tend to increaseturning.

Another feature is “intelligence” of the device 100, which can allow thedevice to interact in an apparently intelligent manner with obstacles,including, for example, bouncing off any obstacles (e.g., walls, etc.)that the device 100 encounters during movement. For example, the shapeof the nose 108 and the materials from which the nose 108 is constructedcan enhance a tendency of the device to bounce off of obstacles and toturn away from the obstacle. Each of these features can contribute tohow the device 100 moves, and will be described below in more detail.

FIG. 1 illustrates a nose 108 that can contribute to the ability of thedevice 100 to deflect off of obstacles. Nose left side 116 a and noseright side 116 b can form the nose 108. The nose sides 116 a and 116 bcan form a shallow point or another shape that helps to cause the device100 to deflect off obstacles (e.g., walls) encountered as the device 100moves in a generally forward direction. The device 100 can includes aspace within the head 118 that increases bounce by making the head moreelastically deformable (i.e., reducing the stiffness). For example, whenthe device 100 crashes nose-first into an obstacle, the space within thehead 118 allows the head of the device 100 to compress, which providesgreater control over the bounce of the device 100 away from the obstaclethan if the head 118 is constructed as a more solid block of material.The space within the head 118 can also better absorb impact if thedevice falls from some height (e.g., a table). The body shoulder 112 andhead side surface 114, especially when constructed from rubber or otherresilient material, can also contribute to the device's tendency todeflect or bounce off of obstacles encountered at a relatively highangle of incidence.

Wireless/Remote Control Embodiments

In some implementations, the device 100 includes a receiver that can,for example, receive commands from a remote control unit. Commands canbe used, for example, to control the device's speed and direction, andwhether the device is in motion or in a motionless state, to name a fewexamples. In some implementations, controls in the remote control unitcan engage and disengage the circuit that connects the power unit (e.g.,battery) to the device's motor, allowing the operator of the remotecontrol to start and stop the device 100 at any time. Other controls(e.g., a joy stick, sliding bar, etc.) in the remote control unit cancause the motor in the device 100 to spin faster or slower, affectingthe speed of the device 100. The controls can send the receiver on thedevice 100 different signals, depending on the commands that correspondto the movement of the controls. Controls can also turn on and off asecond motor attached to a second eccentric load in the device 100 toalter lateral forces for the device 100, thereby changing a tendency ofthe device to turn and thus providing steering control. Controls in aremote control unit can also cause mechanisms in the device 100 tolengthen or shorten one or more of the legs and/or deflecting one ormore of the legs forward, backward, or laterally to provide steeringcontrol.

Leg Motion and Hop

FIGS. 2A through 3B are diagrams that illustrate example forces thatinduce movement of the device 100 of FIG. 1. Some forces are provided bya rotational motor 202, which enable the device 100 to move autonomouslyacross the surface 110. For example, the motor 202 can rotate aneccentric load 210 that generates moment and force vectors 205-215 asshown in FIGS. 2A-3B. Motion of the device 100 can also depend in parton the position of the legs 104 with respect to the counterweight 210attached to the rotational motor 202. For example, placing thecounterweight 210 in front of the front legs 104 a will increase thetendency of the front legs 104 a to provide the primary forward drivingforce (i.e., by focusing more of the up and down forces on the frontlegs). For example, the distance between the counterweight 210 and thetips of the driving legs can be within a range of 20-100% of an averagelength of the driving legs. Moving the counterweight 210 back relativeto the front legs 104 a can cause other legs to contribute more to thedriving forces.

FIG. 2A shows a side view of the example device 100 shown in FIG. 1 andfurther depicts a rotational moment 205 (represented by the rotationalvelocity ω_(m) and motor torque T_(m)) and a vertical force 206represented by F. FIG. 2B shows a top view of the example device 100shown in FIG. 1 and further shows a horizontal force 208 represented byF_(h). Generally, a negative F_(v) is caused by upward movement of theeccentric load as it rotates, while a positive F_(v) can be caused bythe downward movement of the eccentric load and/or the resiliency of thelegs (e.g., as they spring back from a deflected position).

The forces F_(v) and F_(h) cause the device 100 to move in a directionthat is consistent with the configuration in which the leg base 106 b ispositioned in front of the leg tip 106 a. The direction and speed inwhich the device 100 moves can depend, at least in part, on thedirection and magnitude of F_(v) and F_(h). When the vertical force 206,F_(v), is negative, the device 100 body is forced down. This negativeF_(v) causes at least the front legs 104 a to bend and compress. Thelegs generally compress along a line in space from the leg tip to theleg base. As a result, the body will lean so that the leg bends (e.g.,the leg base 106 b flexes (or deflects) about the leg tip 106 a towardsthe surface 110) and causes the body to move forward (e.g., in adirection from the leg tip 106 a towards the leg base 106 b). F_(v),when positive, provides an upward force on the device 100 allowing theenergy stored in the compressed legs to release (lifting the device),and at the same time allowing the legs to drag or hop forward to theiroriginal position. The lifting force F_(v) on the device resulting fromthe rotation of the eccentric load combined with the spring-like legforces are both involved in allowing the device to hop vertically offthe surface (or at least reducing the load on the front legs 104 a) andallowing the legs 104 to return to their normal geometry (i.e., as aresult of the resiliency of the legs). The release of the spring-likeleg forces, along with the forward momentum created as the legs bend,propels the device forward and upward, based on the angle of the lineconnecting the leg tip to the leg base, lifting the front legs 104 a offthe surface 110 (or at least reducing the load on the front legs 104 a)and allowing the legs 104 to return to their normal geometry (i.e., as aresult of the resiliency of the legs).

Generally, two “driving” legs (e.g., the front legs 104 a, one on eachside) are used, although some implementations may include only onedriving leg or more than two driving legs. Which legs constitute drivinglegs can, in some implementations, be relative. For example, even whenonly one driving leg is used, other legs may provide a small amount offorward driving forces. During the forward motion, some legs 104 maytend to drag rather than hop. Hop refers to the result of the motion ofthe legs as they bend and compress and then return to their normalconfiguration—depending on the magnitude of F_(v), the legs can eitherstay in contact with the surface or lift off the surface for a shortperiod of time as the nose is elevated. For example, if the eccentricload is located toward the front of the device 100, then the front ofthe device 100 can hop slightly, while the rear of the device 100 tendsto drag. In some cases, however, even with the eccentric load locatedtoward the front of the device 100, even the back legs 104 c maysometimes hop off the surface, albeit to a lesser extent than the frontlegs 104 a. Depending on the stiffness or resiliency of the legs, thespeed of rotation of the rotational motor, and the degree to which aparticular hop is in phase or out of phase with the rotation of themotor, a hop can range in duration from less than the time required fora full rotation of the motor to the time required for multiple rotationsof the motor. During a hop, rotation of the eccentric load can cause thedevice to move laterally in one direction or the other (or both atdifferent times during the rotation) depending on the lateral directionof rotation at any particular time and to move up or down (or both atdifferent times during the rotation) depending on the vertical directionof rotation at any particular time.

Increasing hop time can be a factor in increasing speed. The more timethat the device spends with some of the leg off the surface 110 (orlightly touching the surface), the less time some of the legs aredragging (i.e., creating a force opposite the direction of forwardmotion) as the device translates forward. Minimizing the time that thelegs drag forward (as opposed to hop forward) can reduce drag caused byfriction of the legs sliding along the surface 110. In addition,adjusting the CG of the device fore and aft can effect whether thedevice hops with the front legs only, or whether the device hops withmost, if not all, of the legs off the ground. This balancing of the hopcan take into account the CG, the mass of the offset weight and itsrotational frequency, F_(v) and its location, and hop forces and theirlocation(s).

Turning of Device

The motor rotation also causes a lateral force 208, F_(h), whichgenerally shifts back and forth as the eccentric load rotates. Ingeneral, as the eccentric load rotates (e.g., due to the motor 202), theleft and right horizontal forces 208 are equal. The turning that resultsfrom the lateral force 208 on average typically tends to be greater inone direction (right or left) while the device's nose 108 is elevated,and greater in the opposite direction when the device's nose 108 and thelegs 104 are compressed down. During the time that the center of theeccentric load 210 is traveling upward (away from the surface 110),increased downward forces are applied to the legs 104, causing the legs104 to grip the surface 110, minimizing lateral turning of the device100, although the legs may slightly bend laterally depending on thestiffness of the legs 104. During the time when the eccentric load 210is traveling downward, the downward force on the legs 104 decreases, anddownward force of the legs 104 on the surface 110 can be reduced, whichcan allow the device to turn laterally during the time the downwardforce is reduced. The direction of turning generally depends on thedirection of the average lateral forces caused by the rotation of theeccentric load 210 during the time when the vertical forces are positiverelative to when the vertical forces are negative. Thus, the horizontalforce 208, F_(h), can cause the device 100 to turn slightly more whenthe nose 108 is elevated. When the nose 108 is elevated, the leg tipsare either off the surface 110 or less downward force is on the frontlegs 104 a which precludes or reduces the ability of the leg tips (e.g.,leg tip 106 a) to “grip” the surface 110 and to provide lateralresistance to turning. Features can be implemented to manipulate severalmotion characteristics to either counteract or enhance this tendency toturn.

The location of the CG can also influence a tendency to turn. While someamount of turning by the device 100 can be a desired feature (e.g., tomake the device's movement appear random), excessive turning can beundesirable. Several design considerations can be made to compensate for(or in some cases to take advantage of) the device's tendency to turn.For example, the weight distribution of the device 100, or morespecifically, the device's CG, can affect the tendency of the device 100to turn. In some implementations, having CG relatively near the centerof the device 100 and roughly centered about the legs 104 can increase atendency for the device 100 to travel in a relatively straight direction(e.g., not spinning around).

Tuning the drag forces for different legs 104 is another way tocompensate for the device's tendency to turn. For example, the dragforces for a particular leg 104 can depend on the leg's length,thickness, stiffness and the type of material from which the leg ismade. In some implementations, the stiffness of different legs 104 canbe tuned differently, such as having different stiffness characteristicsfor the front legs 104 a, rear legs 104 c and middle legs 104 b. Forexample, the stiffness characteristics of the legs can be altered ortuned based on the thickness of the leg or the material used for theleg. Increasing the drag (e.g., by increasing a leg length, thickness,stiffness, and/or frictional characteristic) on one side of the device(e.g., the right side) can help compensate for a tendency of the deviceto turn (e.g., to the left) based on the force F_(h) induced by therotational motor and eccentric load.

Altering the position of the rear legs 104 c is another way tocompensate for the device's tendency to turn. For example, placing thelegs 104 further toward the rear of the device 100 can help the device100 travel in a more straight direction. Generally, a longer device 100that has a relatively longer distance between the front and rear legs104 c may tend to travel in more of a straight direction than a device100 that is shorter in length (i.e., the front legs 104 a and rear legs104 c are closer together), at least when the rotating eccentric load islocated in a relatively forward position on the device 100. The relativeposition of the rearmost legs 104 (e.g., by placing the rearmost leg onone side of the device farther forward or backward on the device thanthe rearmost leg on the other side of the device) can also helpcompensate for (or alter) the tendency to turn.

Various techniques can also be used to control the direction of travelof the device 100, including altering the load on specific legs,adjusting the number of legs, leg lengths, leg positions, leg stiffness,and drag coefficients. As illustrated in FIG. 2B, the lateral horizontalforce 208, F_(h), causes the device 100 to have a tendency to turn asthe lateral horizontal force 208 generally tends to be greater in onedirection than the other during hops. The horizontal force 208, F_(h)can be countered to make the device 100 move in an approximatelystraight direction. This result can be accomplished with adjustments toleg geometry and leg material selection, among other things.

FIG. 3A is a diagram that shows a rear view of the device 100 andfurther illustrates the relationship of the vertical force 206 F_(v) andthe horizontal force 208 F_(h) in relation to each other. This rear viewalso shows the eccentric load 210 that is rotated by the rotationalmotor 202 to generate vibration, as indicated by the rotational moment205.

Drag Forces

FIG. 3B is a diagram that shows a bottom view of the device 100 andfurther illustrates example leg forces 211-214 that are involved withdirection of travel of the device 100. In combination, the leg forces211-214 can induce velocity vectors that impact the predominantdirection of travel of the device 100. The velocity vector 215,represented by T_(load), represents the velocity vector that is inducedby the motor/eccentricity rotational velocity (e.g., induced by theoffset load attached to the motor) as it forces the driving legs 104 tobend, causing the device to lunge forward, and as it generates greaterlateral forces in one direction than the other during hopping. The legforces 211-214, represented by F₁-F₄, represent the reactionary forcesof the legs 104 a 1-104 c 2, respectively, that can be oriented so thelegs 104 a 1-104 c 2, in combination, induce an opposite velocity vectorrelative to Thad. As depicted in FIG. 3B, T_(load) is a velocity vectorthat tends to steer the device 100 to the left (as shown) due to thetendency for there to be greater lateral forces in one direction thanthe other when the device is hopping off the surface 110. At the sametime, the forces F₁-F₂ for the front legs 104 a 1 and 104 a 2 (e.g., asa result of the legs tending to drive the device forward and slightlylaterally in the direction of the eccentric load 210 when the drivinglegs are compressed) and the forces F₃-F₄ for the rear legs 104 c 1 and104 c 2 (as a result of drag) each contribute to steering the device 100to the right (as shown). (As a matter of clarification, because FIG. 3Bshows the bottom view of the device 100, the left-right directions whenthe device 100 is placed upright are reversed.) In general, if thecombined forces F₁-F₄ approximately offset the side component ofT_(load), then the device 100 will tend to travel in a relativelystraight direction.

Controlling the forces F₁-F₄ can be accomplished in a number of ways.For example, the “push vector” created by the front legs 104 a 1 and 104a 2 can be used to counter the lateral component of the motor-inducedvelocity. In some implementations, this can be accomplished by placingmore weight on the front leg 104 a 2 to increase the leg force 212,represented by F₂, as shown in FIG. 3B. Furthermore, a “drag vector” canalso be used to counter the motor-induced velocity. In someimplementations, this can be accomplished by increasing the length ofthe rear leg 104 c 2 or increasing the drag coefficient on the rear leg104 c 2 for the force vector 804, represented by F₄, in FIG. 3B. Asshown, the legs 104 a 1 and 104 a 2 are the device's front right andleft legs, respectively, and the legs 104 c 1 and 104 c 2 are thedevice's rear right and left legs, respectively.

Another technique for compensating for the device's tendency to turn isincreasing the stiffness of the legs 104 in various combinations (e.g.,by making one leg thicker than another or constructing one leg using amaterial having a naturally greater stiffness). For example, a stifferleg will have a tendency to bounce more than a more flexible leg. Leftand right legs 104 in any leg pair can have different stiffnesses tocompensate for the turning of the device 100 induced by the vibration ofthe motor 202. Stiffer front legs 104 a can also produce more bounce.

Another technique for compensating for the device's tendency to turn isto change the relative position of the rear legs 104 c 1 and 104 c 2 sothat the drag vectors tend to compensate for turning induced by themotor velocity. For example, the rear leg 104 c 2 can be placed fartherforward (e.g., closer to the nose 108) than the rear leg 104 c 1.

Leg Shape

Leg geometry contributes significantly to the way in which the device100 moves. Aspects of leg geometry include: locating the leg base infront of the leg tip, curvature of the legs, deflection properties ofthe legs, configurations that result in different drag forces fordifferent legs, including legs that do not necessarily touch thesurface, and having only three legs that touch the surface, to name afew examples.

Generally, depending on the position of the leg tip 106 a relative tothe leg base 106 b, the device 100 can experience different behaviors,including the speed and stability of the device 100. For example, if theleg tip 106 a is nearly directly below the leg base 106 b when thedevice 100 is positioned on a surface, movement of the device 100 thatis caused by the motor 202 can be limited or precluded. This is becausethere is little or no slope to the line in space that connects the legtip 106 a and the leg base 106 b. In other words, there is no “lean” inthe leg 104 between the leg tip 106 a and the leg base 106 b. However,if the leg tip 106 a is positioned behind the leg base 106 b (e.g.,farther from the nose 108), then the device 100 can move faster, as theslope or lean of the legs 104 is increased, providing the motor 202 witha leg geometry that is more conducive to movement. In someimplementations, different legs 104 (e.g., including different pairs, orleft legs versus right legs) can have different distances between legtips 106 a and leg bases 106 b.

In some implementations, the legs 104 are curved (e.g., leg 104 a shownin FIG. 2A, and legs 104 shown in FIG. 1). For example, because the legs104 are typically made from a flexible material, the curvature of thelegs 104 can contribute to the forward motion of the device 100. Curvingthe leg can accentuate the forward motion of the device 100 byincreasing the amount that the leg compresses relative to a straightleg. This increased compression can also increase device hopping, whichcan also increase the tendency for random motion, giving the device anappearance of intelligence and/or a more life-like operation. The legscan also have at least some degree of taper from the leg base 106 b tothe leg tip 106 a, which can facilitate easier removal from a moldduring the manufacturing process.

The number of legs can vary in different implementations. In general,increasing the number of legs 104 can have the effect of making thedevice more stable and can help reduce fatigue on the legs that are incontact with the surface 110. Increasing the number of legs can alsoaffect the location of drag on the device 100 if additional leg tips 106a are in contact with the surface 110. In some implementations, however,some of the legs (e.g., middle legs 104 b) can be at least slightlyshorter than others so that they tend not to touch the surface 110 orcontribute less to overall friction that results from the leg tips 106 atouching the surface 110. For example, in some implementations, the twofront legs 104 a (e.g., the “driving” legs) and at least one of the rearlegs 104 c are at least slightly longer than the other legs. Thisconfiguration helps increase speed by increasing the forward drivingforce of the driving legs. In general, the remaining legs 104 can helpprevent the device 100 from tipping over by providing additionalresiliency should the device 100 start to lean toward one side or theother.

In some implementations, one or more of the “legs” can include anyportion of the device that touches the ground. For example, the device100 can include a single rear leg (or multiple rear legs) constructedfrom a relatively inflexible material (e.g., rigid plastic), which canresemble the front legs or can form a skid plate designed to simply dragas the front legs 104 a provide a forward driving force. The oscillatingeccentric load can repeat tens to several hundred times per second,which causes the device 100 to move in a generally forward motion as aresult of the forward momentum generated when F_(v) is negative.

Leg geometry can be defined and implemented based on ratios of variousleg measurements, including leg length, diameter, and radius ofcurvature. One ratio that can be used is the ratio of the radius ofcurvature of the leg 104 to the leg's length. As just one example, ifthe leg's radius of curvature is 49.14 mm and the leg's length is 10.276mm, then the ratio is 4.78. In another example, if the leg's radius ofcurvature is 2.0 inches and the leg's length is 0.4 inches, then theratio is 5.0. Other leg 104 lengths and radii of curvature can be used,such as to produce a ratio of the radius of curvature to the leg'slength that leads to suitable movement of the device 100. In general,the ratio of the radius of curvature to the leg's length can be in therange of 2.5 to 20.0. The radius of curvature can be approximatelyconsistent from the leg base to the leg tip. This approximate consistentcurvature can include some variation, however. For example, some taperangle in the legs may be required during manufacturing of the device(e.g., to allow removal from a mold). Such a taper angle may introduceslight variations in the overall curvature that generally do not preventthe radius of curvature from being approximately consistent from the legbase to the leg tip.

Another ratio that can be used to characterize the device 100 is a ratiothat relates leg 104 length to leg diameter or thickness (e.g., asmeasured in the center of the leg or as measured based on an average legdiameter throughout the length of the leg and/or about the circumferenceof the leg). For example, the length of the legs 104 can be in the rangeof 0.2 inches to 0.8 inches (e.g., 0.405 inches) and can be proportionalto (e.g., 5.25 times) the leg's thickness in the range of 0.03 to 0.15inch (e.g., 0.077 inch). Stated another way, legs 104 can be about 15%to 25% as thick as they are long, although greater or lesser thicknesses(e.g., in the range of 5% to 60% of leg length) can be used. Leg 104lengths and thicknesses can further depend on the overall size of thedevice 100. In general, at least one driving leg can have a ratio of theleg length to the leg diameter in the range of 2.0 to 20.0 (i.e., in therange of 5% to 50% of leg length). In some implementations, a diameterof at least 10% of the leg length may be desirable to provide sufficientstiffness to support the weight of the device and/or to provide desiredmovement characteristics.

Leg Material

The legs are generally constructed of rubber or other flexible butresilient material (e.g., polystyrene-butadiene-styrene with a durometernear 65, based on the Shore A scale, or in the range of 55-75, based onthe Shore A scale). Thus, the legs tend to deflect when a force isapplied. Generally, the legs include a sufficient stiffness andresiliency to facilitate consistent forward movement as the devicevibrates (e.g., as the eccentric load 210 rotates). The legs 104 arealso sufficiently stiff to maintain a relatively wide stance when thedevice 100 is upright yet allow sufficient lateral deflection when thedevice 100 is on its side to facilitate self-righting, as furtherdiscussed below.

The selection of leg materials can have an effect on how the device 100moves. For example, the type of material used and its degree ofresiliency can affect the amount of bounce in the legs 104 that iscaused by the vibration of the motor 202 and the counterweight 210. As aresult, depending on the material's stiffness (among other factors,including positions of leg tips 106 b relative to leg bases 106 a), thespeed of the device 100 can change. In general, the use of stiffermaterials in the legs 104 can result in more bounce, while more flexiblematerials can absorb some of the energy caused by the vibration of themotor 202, which can tend to decrease the speed of the device 100.

Frictional Characteristics

Friction (or drag) force equals the coefficient of friction multipliedby normal force. Different coefficients of friction and the resultingfriction forces can be used for different legs. As an example, tocontrol the speed and direction (e.g., tendency to turn, etc.), the legtips 106 a can have varying coefficients of friction (e.g., by usingdifferent materials) or drag forces (e.g., by varying the coefficientsof friction and/or the average normal force for a particular leg). Thesedifferences can be accomplished, for example, by the shape (e.g.,pointedness or flatness, etc.) of the leg tips 106 a as well as thematerial of which they are made. Front legs 104 a, for example, can havea higher friction than the rear legs 104 c. Middle legs 104 b can haveyet different friction or can be configured such that they are shorterand do not touch the surface 110, and thus do not tend to contribute tooverall drag. Generally, because the rear legs 104 c (and the middlelegs 104 b to the extent they touch the ground) tend to drag more thanthey tend to create a forward driving force, lower coefficients offriction and lower drag forces for these legs can help increase thespeed of the device 100. Moreover, to offset the motor force 215, whichcan tend to pull the device in a left or right direction, left and rightlegs 104 can have different friction forces. Overall, coefficients offriction and the resulting friction force of all of the legs 104 caninfluence the overall speed of the device 100. The number of legs 104 inthe device 100 can also be used to determine coefficients of friction tohave in (or design into) each of the individual legs 104. As discussedabove, the middle legs 104 b do not necessarily need to touch thesurface 110. For example, middle (or front or back) legs 104 can bebuilt into the device 100 for aesthetic reasons, e.g., to make thedevice 100 appear more life-like, and/or to increase device stability.In some implementations, devices 100 can be made in which only three (ora small number of) legs 104 touch the ground, such as two front legs 104a and one or two rear legs 104 c.

The motor 202 is coupled to and rotates a counterweight 210, oreccentric load, that has a CG that is off axis relative to therotational axis of the motor 202. The rotational motor 202 andcounterweight 210, in addition to being adapted to propel the device100, can also cause the device 100 to tend to roll, e.g., about the axisof rotation of the rotational motor 200. The rotational axis of themotor 202 can have an axis that is approximately aligned with alongitudinal CG of the device 100, which is also generally aligned witha direction of movement of the device 100.

FIG. 2A also shows a battery 220 and a switch 222. The battery 220 canprovide power to the motor 202, for example, when the switch 222 is inthe “ON” position, thus connecting an electrical circuit that deliverselectric current to the motor 202. In the “OFF” position of the switch222, the circuit is broken, and no power reaches the motor 202. Thebattery 220 can be located within or above a battery compartment cover224, accessible, for example, by removing a screw 226, as shown in FIGS.2A and 3B. The placement of the battery 220 and the switch 222 partiallybetween the legs of the device 100 can lower the device's CG and help toprevent tipping. Locating the motor 202 lower within the device 100 alsoreduces tipping. Having legs 104 on the sides of a device 100 provides aspace (e.g., between the legs 104) to house the battery 220, the motor204 and the switch 222. Positioning these components 204, 220 and 222along the underside of the device 100 (e.g., rather than on top of thedevice housing) effectively lowers the CG of the device 100 and reducesits likelihood of tipping.

The device 100 can be configured such that the CG is selectivelypositioned to influence the behavior of the device 100. For example, alower CG can help to prevent tipping of the device 100 during itsoperation. As an example, tipping can occur as a result of the device100 moving at a high rate of speed and crashing into an obstacle. Inanother example, tipping can occur if the device 100 encounters asufficiently irregular area of the surface on which it is operating. TheCG of the device 100 can be selectively manipulated by positioning themotor, switch, and battery in locations that provide a desired CG, e.g.,one that reduces the likelihood of inadvertent tipping. In someimplementations, the legs can be configured so that they extend from theleg tip 106 a below the CG to a leg base 106 b that is above the CG,allowing the device 100 to be more stable during its operation. Thecomponents of the device 100 (e.g., motor, switch, battery, and housing)can be located at least partially between the legs to maintain a lowerCG. In some implementations, the components of the device (e.g., motor,switch and battery) can be arranged or aligned close to the CG tomaximize forces caused by the motor 202 and the counterweight 210.

Self-Righting

Self-righting, or the ability to return to an upright position (e.g.,standing on legs 104), is another feature of the device 100. Forexample, the device 100 can occasionally tip over or fall (e.g., fallingoff a table or a step). As a result, the device 100 can end up on itstop or its side. In some implementations, self-righting can beaccomplished using the forces caused by the motor 202 and thecounterweight 210 to cause the device 100 to roll over back onto itslegs 104. Achieving this result can be helped by locating the device'sCG proximal to the motor's rotational axis to increase the tendency forthe entire device 100 to roll. This self-righting generally provides forrolling in the direction that is opposite to the rotation of the motor202 and the counterweight 210.

Provided that a sufficient level of roll tendency is produced based onthe rotational forces resulting from the rotation of the motor 202 andthe counterweight 210, the outer shape of the device 100 can be designedsuch that rolling tends to occur only when the device 100 is on itsright side, top side, or left side. For example, the lateral spacingbetween the legs 104 can be made wide enough to discourage rolling whenthe device 100 is already in the upright position. Thus, the shape andposition of the legs 104 can be designed such that, when self-rightingoccurs and the device 100 again reaches its upright position aftertipping or falling, the device 100 tends to remain upright. Inparticular, by maintaining a flat and relatively wide stance in theupright position, upright stability can be increased, and, byintroducing features that reduce flatness when not in an uprightposition, the self-righting capability can be increased.

To assist rolling from the top of the device 100, a high point 120 or aprotrusion (e.g., appendage 105) can be included on the top of thedevice 100. The high point 120 or other protrusion can prevent thedevice from resting flat on its top. In addition, the high point 120 orother protrusion can prevent F_(h) from becoming parallel to the forceof gravity, and as a result, F_(h) can provide enough moment to causethe device to roll, enabling the device 100 to roll to an uprightposition or at least to the side of the device 100. In someimplementations, the high point 120 or other protrusion can berelatively stiff (e.g., a relatively hard plastic), while the topsurface of the head 118 can be constructed of a more resilient materialthat encourages bouncing. Bouncing of the head 118 of the device whenthe device is on its back can facilitate self-righting by allowing thedevice 100 to roll due to the forces caused by the motor 202 and thecounterweight 210 as the head 118 bounces off the surface 110.

Rolling from the side of the device 100 to an upright position can befacilitated by using legs 104 that are sufficiently flexible incombination with the space 124 (e.g., underneath the device 100) forlateral leg deflection to allow the device 100 to roll to an uprightposition. This space can allow the legs 104 to bend during the roll,facilitating a smooth transition from side to bottom. The shoulders 112on the device 100 can also decrease the tendency for the device 100 toroll from its side onto its back, at least when the forces caused by themotor 202 and the counterweight 210 are in a direction that opposesrolling from the side to the back. At the same time, the shoulder on theother side of the device 100 (even with the same configuration) can bedesigned to avoid preventing the device 100 from rolling onto its backwhen the forces caused by the motor 202 and the counterweight 210 are ina direction that encourages rolling in that direction. Furthermore, useof a resilient material for the shoulder can increase bounce, which canalso increase the tendency for self-righting (e.g., by allowing thedevice 100 to bounce off the surface 110 and allowing the counterweightforces to roll the device while airborne). Self-righting from the sidecan further be facilitated by adding appendages along the side(s) of thedevice 100 that further separate the rotational axis from the surfaceand increase the forces caused by the motor 202 and the counterweight210.

The position of the battery on the device 100 can affect the device'sability to roll and right itself. For example, the battery can beoriented on its side, positioned in a plane that is both parallel to thedevice's direction of movement and perpendicular to the surface 110 whenthe device 100 is upright. This positioning of the battery in thismanner can facilitate reducing the overall width of the device 100,including the lateral distance between the legs 104, making the device100 more likely to be able to roll.

FIG. 4 shows an example front view indicating a center of gravity (CG)402, as indicated by a large plus sign, for the device 100. This viewillustrates a longitudinal CG 402 (i.e., a location of a longitudinalaxis of the device 100 that runs through the device CG). In someimplementations, the device's components are aligned to place thelongitudinal CG close to (e.g., within 5-10% as a percentage of theheight of the device) the physical longitudinal centerline of thedevice, which can reduce the rotational moment of inertia of the device,thereby increasing or maximizing the forces on the device as therotational motor rotates the eccentric load. As discussed above, thiseffect increases the tendency of the device 100 to roll, which canenhance the self-righting capability of the device. FIG. 4 also shows aspace 404 between the legs 104 and the underside 122 of the device 100(including the battery compartment cover 224), which can allow the legs104 to bend inward when the device is on its side, thereby facilitatingself-righting of the device 100. FIG. 4 also illustrates a distance 406between the pairs or rows of legs 104. Increasing the distance 406 canhelp prevent the device 100 from tipping. However, keeping the distance406 sufficiently low, combined with flexibility of the legs 104, canimprove the device's ability to self-right after tipping. In general, toprevent tipping, the distance 406 between pairs of legs needs to beincreased proportionally as the CG 402 is raised.

The device high point 120 is shown in FIG. 4, although the high point120 generally has limited effect in the presence of the top climberappendage 105. The size or height of the high point 120 (in the absenceof the top climber appendage 105) or the top climber appendage 105 canbe sufficiently large enough to prevent the device 100 from simply lyingflat on its back after tipping, yet sufficiently small enough to helpfacilitate the device's roll and to force the device 100 off its backafter tipping. A larger or higher high point 120 can sometimes becombined with “pectoral fins” or other side protrusions to increase the“roundness” of the device.

The tendency to roll of the device 100 can depend on the general shapeof the device 100. For example, a device 100 that is generallycylindrical, particularly along the top of the device 100, can rollrelatively easily. However, rolling can also occur when the device 100includes the top climber-appendage 105, at least if the device 100 isadapted to bounce or otherwise hop high enough off of a surface to rollfrom one side of the top climber appendage 105 to the other side. Thus,even if the top of the device is not round, as is the case for thedevice shown in FIG. 4 that includes straight top sides 407 a and 407 b,the geometry of the top of the device 100 can still facilitate rolling.This rolling capability is especially true if distances 408 and 410 arerelatively equal and each approximately defines the radius of thegenerally cylindrical shape of the device 100. Distance 408, forexample, is the distance from the device's longitudinal CG 402 to thetop of the shoulder 112. Distance 410 is the distance from the device'slongitudinal CG 402 to the high point 120. Further, having a length ofsurface 407 b (i.e., between the top of the shoulder 112 and the highpoint 120) that is less than the distances 408 and 410 can also increasethe tendency of the device 100 to roll. Moreover, if the device'slongitudinal CG 402 is positioned relatively close to the center of thecylinder that approximates the general shape of the device 100, thenroll of the device 100 is further enhanced, as the forces caused by themotor 202 and the counterweight 210 are generally more centered. Thedevice 100 can stop rolling once the rolling action places the device100 on its legs 104, which provide a wide stance and serve to interruptthe generally cylindrical shape of the device 100.

FIG. 5 shows an example side view indicating a center of gravity (CG)502, as indicated by a large plus sign, for the device 100. This viewalso shows a motor axis 504 which, in this example, closely aligns withthe longitudinal component of the CG 502. The location of the CG 502depends on, e.g., the mass, thickness, and distribution of the materialsand components included in the device 100. In some implementations, theCG 502 can be farther forward or farther back from the location shown inFIG. 5. For example, the CG 502 can be located toward the rear end ofthe switch 222 rather than toward the front end of the switch 222 asillustrated in FIG. 5. In general, the CG 502 of the device 100 can besufficiently far behind the front driving legs 104 a and the rotatingeccentric load (and sufficiently far in front of the rear legs 104 c) tofacilitate front hopping and rear drag, which can increase forward driveand provide a controlled tendency to go straight (or turn if desired)during hops. For example, the CG 502 can be positioned roughly halfway(e.g., in the range of roughly 40-60% of the distance) between the frontdriving legs 104 a and the rear dragging legs 104 c. Also, aligning themotor axis with the longitudinal CG can enhance forces caused by themotor 202 and the counterweight. In some implementations, thelongitudinal component of the CG 502 can be near to the center of theheight of the device (e.g., within about 3% of the CG as a proportion ofthe height of the device). Generally, configuring the device 100 suchthat the CG 502 is closer to the center of the height of the device willenhance the rolling tendency, although greater distances (e.g., withinabout 5% or within about 20% of the CG as a proportion of the height ofthe device) are acceptable in some implementations. Similarly,configuring the device 100 such that the CG 502 is within about 3-6% ofthe motor axis 504 as a percentage of the height of the device can alsoenhance the rolling tendency.

FIG. 5 also shows an approximate alignment of the battery 220, theswitch 222 and the motor 202 with the longitudinal component of the CG502. Although a sliding switch mechanism 506 that operates the on/offswitch 222 hangs below the underside of the device 100, the overallapproximate alignment of the CG of the individual components 220, 222and 202 (with each other and with the CG 502 of the overall device 100)contributes to the ability of the device 100 to roll, and thus rightitself. In particular, the motor 202 is centered primarily along thelongitudinal component of the CG 502.

In some implementations, the high point 120 can be located behind the CG502, which can facilitate self-righting in combination with theeccentric load attached to the motor 202 being positioned near the nose108. As a result, if the device 100 is on its side or back, the nose endof the device 100 tends to vibrate and bounce (more so than the tail endof the device 100), which facilitates self-righting as the forces of themotor and eccentric load tend to cause the device to roll.

FIG. 5 also shows some of the sample dimensions of the device 100. Forexample, a distance 508 between the CG 502 and a plane that passesthrough the leg tips 106 a on which the device 100 rests when upright ona flat surface 110 can be approximately 0.36 inches. In someimplementations, this distance 508 is approximately 50% of the totalheight of the device (see FIGS. 7A & 7B), although other distances 508may be used in various implementations (e.g., from about 40-60%). Adistance 510 between the rotational axis 504 of the motor 202 and thesame plane that passes through the leg tips 106 a is approximately thesame as the distance 508, although variations (e.g., 0.34 inches fordistance 510 vs. 0.36 inches for distance 508) may be used withoutmaterially impacting desired functionality. Greater variations (e.g.,0.05 inches or even 0.1 inches) may be used in some implementations.

A distance 512 between the leg tip 106 a of the front driving legs 104 aand the leg tip 106 a of the rearmost leg 104 c can be approximately0.85 inches, although various implementations can include other valuesof the distance 512 (e.g., between about 40% and about 75% of the lengthof the device 100). In some implementations, locating the front drivinglegs 104 a behind the eccentric load 210 can facilitate forward drivingmotion and randomness of motion. For example, a distance 514 between alongitudinal centerline of the eccentric load 210 and the tip 106 a ofthe front leg 104 a can be approximately 0.36 inches. Again, otherdistances 514 can be used (e.g., between about 5% and about 30% of thelength of the device 100 or between about 10% and about 60% of thedistance 512). A distance 516 between the front of the device 100 andthe CG 502 can be about 0.95 inches. In various implementations, thedistance 516 may range from about 40-60% of the length of the device100, although some implementations may include front or rear protrusionswith a low mass that add to the length of the device but do notsignificantly impact the location of the CG 502 (i.e., therefore causingthe CG 502 to be outside of the 40-60% range).

FIG. 9A shows an example environment 900 in which the device 100 canoperate and climb inside a conduit 901. Conduits can be substantiallylevel or sloped, or may include combinations of sloped and level areas.Conduits can allow the device 100 to travel at any angle, including aninverted position. In the example shown in FIG. 9A, the environment 900includes an arena 902 in which one or more devices 100 can operate. Thearena 902 includes an opening 904 that leads to a connecting pathway 906in which the device 100 is shown. The connecting pathway 906 isconnected to the conduit 901 toward which the device 100 is pointed inthis illustration (e.g., based on the position of the head and tail ofthe device 100). Sections of the environment 900, including a curvedpathway 910 and other sections not shown in FIG. 9A, can be connected atconnection points 912. For example, the connection points 912 cancomprise snap-together parts (e.g., tongue-and-groove) of varioussections and/or components of the environment 900 (e.g., the connectingpathway 906 and the conduit 901), although other ways of connectingsections of the environment 900 can be used.

The conduit 901 can be entirely or substantially enclosed. For example,in addition to the conduit 901 having a floor surface that can serve asa surface for the legs 104, a ceiling surface can exist that is oppositeand substantially parallel to the floor surface. The floor surface andceiling surface are interchangeable since the device 100 can travelright-side-up or up-side-down in any conduit or tube. The ceilingsurface, for example, can be a surface that is contacted by the topclimber-appendage 105 as the device 100 travels through the conduit 901.The conduit 901 can also include opposing wall surfaces (or partial wallsurfaces) which can, in combination with the floor surface and theceiling surface, serve to contain the device 100 as it travels throughthe conduit 901. Other configurations of surfaces can be used. Climbingby the device 100 occurs as vibration induced by the vibrating mechanismcauses the legs 104 and the one or more top climber-appendages 105 torepeatedly flex, pushing the device 100 forward (e.g., inside a tube).While the device 100 moves forward, the legs 104 and the one or more topclimber-appendages 105 maintain substantially constant contact with thesubstantially parallel surfaces (e.g., the floor surface and the ceilingsurface). The device 100 may lose contact with either surface for asmall percentage of the time, but movement by the device 100 isgenerally maintained in the forward direction. As a result, the device100 can climb through any suitable tube that is sized such that the legs104 and the one or more climber-appendages 105 contact the floor andceiling surfaces to cause the device to move forward. Climbing by thedevice 100 can occur at any angle and orientation of the device 100. Forexample, the device 100 can climb straight up or at any angle upward.The device 100 can also descend downward at any angle, or can climbsubstantially horizontally. The device 100 can be right-side-up orup-side-down and still climb and descend. When the device 100 isdescending, sufficient drag is provided by the legs 104 and the one ormore climber-appendages 105 so as to provide a controlled decent.

During operation of the device 100, e.g., as the device 100 travelsthrough the conduit 901, the legs 104 and the top climber-appendage 105(or side climber-appendages 105 a and 105 b) are subjected to or produceforces that cause the device 100 to climb. For example, the forcesinclude a net force in a direction generally defined by an offsetbetween the appendage bases and the appendage tips of the two or moreappendages. As a result, the device 100 climbs when the net forceexceeds an opposing gravitational force on the device 100. Specifically,the forces exerted by the legs 104 and the top climber-appendages 105(or side climber-appendages 105 a and 105 b) (e.g., as the device 100vibrates up and down and/or side to side) provide a ratcheting effect,enabling the device 100 to climb between substantially vertical opposingsurfaces (e.g., the floor surface and the ceiling surface). Theratcheting effect can result from the legs 104 bending and the topclimber-appendages 105 (or side climber-appendages 105 a and 105 b)sliding forward as the center of gravity of the device 100 moves towardthe floor surface (i.e., the surface that the legs 104 are contacting)and from the top climber-appendages 105 (or side climber-appendages 105a and 105 b) bending and the legs 104 sliding forward as the center ofgravity of the device 100 moves toward the ceiling surface (i.e., thesurface that the top climber-appendages 105 (or side climber-appendages105 a and 105 b) are contacting).

FIG. 9B shows the example environment 900 in which the device 100 hasclimbed inside of and nearly to the top of the conduit 901. Because noother section is attached to the end of the conduit 901 in thisillustration, when the device 100 reaches the open end of the conduit901, the device 100 can fall to the table or floor upon which theenvironment 900 is situated. In some implementations, other sections ofthe environment 900 can be included, e.g., to provide continuity for thedevice 100 after it has completed its climb through the conduit 901.

In some implementations, the speed of the device 100 can be controlledor at least influenced by the slope of the conduit 901 or the materialsof which it is made. In some implementations, the gap between eachsurface (e.g., the ceiling surface) and the corresponding appendage(s)(e.g., the top climber-appendage 105) can also affect the speed of thedevice 100. For example, the fastest speed of the device 100 can beachieved when the gap provides an amount of wiggle room for the device100 that generally minimizes any rearward forces caused by drag relativeto the forward forces induced by vibration, e.g., enabling an efficientratcheting effect (and thus a faster climb rate). In someimplementations, different gaps can be used for different sections ofthe conduit 901 having different slopes or different radii of curvature.For example, gaps can be graduated to coorespond to the slope.

FIG. 9C shows an example loop conduit 950 in the shape of a double loop.For example, the device 100 can enter the loop conduit 950 at anentrance 952. While traveling through the loop conduit 950, the device100 can make two 360-degree loops before exiting a terminal end 954 ofthe loop conduit 950. In some implementations, the device 100 canundergo a twist, or travel in a cork-screw fashion through the loopconduit 950. For example, substantially parallel ceiling and floorsurfaces can twist to cause the device 100 to twist as it travels alongthe parallel surfaces. As an alternative, grooves (or some other changesin shape) that are built into the interior of the loop conduit 950 canaffect the cork-screw motion (e.g., by guiding the topclimber-appendages 105 or side climber-appendages 105 a and 105 bthrough a twist).

In some implementations, two or more appendages can be attached to theinterior of the conduit (e.g., as “conduit appendages”), and can contactthe body of the device 100. For example, the conduit 901 can include,within its interior surfaces (e.g., on the ceiling surface), multipleconduit appendages as shown in FIG. 9D. In some implementations, thetips of the conduit appendages can contact the top edge of the device100 as it moves through the conduit 901. For example, the conduitappendages can be disposed such that the tips are in the forwarddirection relative to the appendage bases. In some implementations, theconduit appendages can be spaced, e.g., at substantially even intervals,so that at least one conduit appendage is adjacent to the top edge ofthe device 100 at all times, and thus able to contact the device 100during vibrations of the device. In this way, the conduit appendages areadapted to allow the device 100 to climb a vertical conduit (e.g., theconduit 901). In some implementations, rows of conduit appendages can beused, e.g., to contact the top of the device 100 at different positionslaterally. Conduit appendages can have different elasticities than theappendages that are on the device 100 itself.

In some implementations, two or more climber-appendages can be attachedto the device 100. For example, the conduit (e.g., the conduit 901), thedevice's body, and the two or more climber-appendages can be configuredsuch that each of the two or more climber-appendages repeatedly contactan internal surface of the conduit, where the contact is for sufficientperiods of time to produce generally forward motion. In someimplementations, at least one of the climber-appendages is substantiallycontinuously in contact with an internal surface of the conduit. Forexample, when the climber-appendages include one or more topclimber-appendages 105, the in-contact internal surface of the conduit901 is the ceiling surface. In another example, when theclimber-appendages include one or more side climber-appendages 105 a-105b, the in-contact internal surfaces of the conduit 901 can include theside wall surfaces.

When two or more appendages (e.g., climber-appendages) are attached tothe device 100, vibration of the device 100 causes at least one of thetwo or more climber-appendages to deflect in a direction opposite theforward direction (i.e., as the vibration causes the device 100 to movetoward a surface that the particular climber-appendage contacts). Forexample, the deflection occurs without substantial slipping of the atleast one appendage on a corresponding internal surface (e.g., theceiling surface) when net forces on the at least one appendage aretoward the corresponding internal surface (e.g., toward the ceilingsurface). At the same time, resiliency of the at least oneclimber-appendage causes the at least one climber-appendage to deflectin the forward direction when net forces on the at least oneclimber-appendage are away from the corresponding internal surface(e.g., the ceiling surface). The device 100 can be configured such thatthe forward deflection generally produces insufficient backward forcesto overcome the forward forces produced by one or more appendages on theopposite side of the device 100.

In some implementations, additional or alternative appendages can beused. FIGS. 15A-15D illustrate an alternative embodiment of a vibrationpowered device 1500. FIG. 15A is a side view of the alternativevibration powered device 1500. FIG. 15B is a top view of the alternativevibration powered device 1500. FIG. 15C is a front view of thealternative vibration powered device 1500. FIG. 15D is a side view ofthe alternative vibration powered device 1500 as it moves through anexample upwardly curved conduit 1520. FIGS. 15A-15C include exampledimensions (e.g., in millimeters) to show an example of relativedimensions of the components. The device 1500 includes appendages 1505,1510, and 1515. In the embodiment illustrated in FIGS. 15A-15D, thedevice 1500 includes dual primary top climber-appendages 1505 a and 1505b, although only one primary top climber-appendage 1505 can be used(e.g., similar to the top climber-appendage 105 located toward the frontof device 100 as shown in FIG. 7B). The device 1500 also includes asecondary top climber-appendage 1510 located behind the primary climberappendages 1505 a and 1505 b. The secondary top climber-appendage 1510can assist in maintaining forward motion. In some embodiments, thesecondary top climber-appendage 1510 may come into contact with an upperinternal surface 1530 of a curved conduit 1520 only (or may onlycontribute to forward motion) when rounding tight turns. The primary topclimber-appendages 1505 a and 1505 b are located toward the front ofdevice 1500 at a location that is significantly toward the front of thedevice 1500 from a middle point between the first and last legs 104.When navigating a tight upward turn, the midpoint between the front andrear legs 104 tends to align with the center of the upward turn. Theprimary top climber-appendages 1505 a and 1505 b therefore may losecontact with the upper internal surface 1530 when the radius of the turnis sufficiently tight. The tip of the secondary top climber-appendage1510 can be located close to the centerline between the front and rearlegs 104, and can therefore keep continuous or substantially continuouscontact with the upper inner surface 1530 and help maintain forwardmotion. Additional secondary front legs 1515, which may only come intocontact with a lower internal surface 1525 of the conduit 1520 inrelatively tight upward curves, can also contribute to forward motion.

Random Motion

By introducing features that increase randomness of motion of the device100, the device 100 can appear to behave in an animate way, such as likea crawling bug or other organic life-form. The random motion can includeinconsistent movements, for example, rather than movements that tend tobe in straight lines or continuous circles. As a result, the device 100can appear to roam about its surroundings (e.g. in an erratic orserpentine pattern) instead of moving in predictable patterns. Randommotion can occur, for example, even while the device 100 is moving inone general direction.

In some implementations, randomness can be achieved by changing thestiffness of the legs 104, the material used to make the legs 104,and/or by adjusting the inertial load on various legs 104. For example,as leg stiffness is reduced, the amount of device hopping can bereduced, thus reducing the appearance of random motion. When the legs104 are relatively stiff, the legs 104 tend to induce hopping, and thedevice 100 can move in a more inconsistent and random motion.

While the material that is selected for the legs 104 can influence legstiffness, it can also have other effects. For example, the leg materialcan be manipulated to attract dust and debris at or near the leg tips106 a, where the legs 104 contact the surface 110. This dust and debriscan cause the device 100 to turn randomly and change its pattern ofmotion. This can occur because the dust and debris can alter the typicalfrictional characteristics of the legs 104.

The inertial load on each leg 104 can also influence randomness ofmotion of the device 100. As an example, as the inertial load on aparticular leg 104 is increased, that portion of the device 100 can hopat higher amplitude, causing the device 100 to land in differentlocations.

In some implementations, during a hop and while at least some legs 104of the device 100 are airborne (or at least applying less force to thesurface 110), the motor 202 and the counterweight 210 can cause somelevel of mid-air turning and/or rotating of the device 100. This canprovide the effect of the device landing or bouncing in unpredictableways, which can further lead to random movement.

In some implementations, additional random movement can result fromlocating front driving legs 104 a (i.e., the legs that primarily propelthe device 100 forward) behind the motor's counterweight. This can causethe front of the device 100 to tend to move in a less straight directionbecause the counterweight is farther from legs 104 that would otherwisetend to absorb and control its energy. An example lateral distance fromthe center of the counterweight to the tip of the first leg of 0.36inches compared to an example leg length of 0.40 inches. Generally, thedistance 514 from the longitudinal centerline of the counterweight tothe tip 106 a of the front leg 104 a may be approximately the same asthe length of the leg but the distance 514 can vary in the range of50-150% of the leg length.

In some implementations, additional appendages can be added to the legs104 (and to the housing 102) to provide resonance. For example, flexibleprotrusions that are constantly in motion in this way can contribute tothe overall randomness of motion of the device 100 and/or to thelifelike appearance of the device 100. Using appendages of differentsizes and flexibilities can magnify the effect.

In some implementations, the battery 220 can be positioned near the rearof the device 100 to increase hop. Doing so positions the weight of thebattery 220 over the rearmost legs 104, reducing load on the front legs104 a, which can allow for more hop at the front legs 104 a. In general,the battery 220 can tend to be heavier than the switch 222 and motor202, thus placement of the battery 220 nearer the rear of the device 100can elevate the nose 108, allowing the device 100 to move faster.

In some implementations, the on/off switch 222 can be oriented along thebottom side of the device 100 between the battery 220 and the motor 204such that the switch 222 can be moved back and forth laterally. Such aconfiguration, for example, helps to facilitate reducing the overalllength of the device 100. Having a shorter device can enhance thetendency for random motion.

Speed of Movement

In addition to random motion, the speed of the device 100 can contributeto the life-like appearance of the device 100. Factors that affect speedinclude the vibration frequency and amplitude that are produced by themotor 202 and counterweight 210, the materials used to make the legs104, leg length and deflection properties, differences in leg geometry,and the number of legs.

Vibration frequency (e.g., based on motor rotation speed) and devicespeed are generally directly proportional. That is, when the oscillatingfrequency of the motor 202 is increased and all other factors are heldconstant, the device 100 will tend to move faster. An exampleoscillating frequency of the motor is in the range of 7000 to 9000 rpm.

Leg material has several properties that contribute to speed. Legmaterial friction properties influence the magnitude of drag force onthe device. As the coefficient of friction of the legs increases, thedevice's overall drag will increase, causing the device 100 to slowdown. As such, the use of leg material having properties promoting lowfriction can increase the speed of the device 100. In someimplementations, polystyrene-butadiene-styrene with a durometer near 65(e.g., based on the Shore A scale) can be used for the legs 104. Legmaterial properties also contribute to leg stiffness which, whencombined with leg thickness and leg length, determines how much hop adevice 100 will develop. As the overall leg stiffness increases, thedevice speed will increase. Longer and thinner legs will reduce legstiffness, thus slowing the device's speed.

Appearance of Intelligence

“Intelligent” response to obstacles is another feature of the device100. For example, “intelligence” can prevent a device 100 that comes incontact with an immoveable object (e.g., a wall) from futilely pushingagainst the object. The “intelligence” can be implemented usingmechanical design considerations alone, which can obviate the need toadd electronic sensors, for example. For example, turns (e.g., left orright) can be induced using a nose 108 that introduces a deflection orbounce in which a device 100 that encounters an obstacle immediatelyturns to a near incident angle.

In some implementations, adding a “bounce” to the device 100 can beaccomplished through design considerations of the nose and the legs 104,and the speed of the device 100. For example, the nose 108 can include aspring-like feature. In some implementations, the nose 108 can bemanufactured using rubber, plastic, or other materials (e.g.,polystyrene-butadiene-styrene with a durometer near 65, or in the rangeof 55-75, based on the Shore A scale). The nose 108 can have a pointed,flexible shape that deflects inward under pressure. Design andconfiguration of the legs 104 can allow for a low resistance to turningduring a nose bounce. Bounce achieved by the nose can be increased, forexample, when the device 100 has a higher speed and momentum.

In some implementations, the resiliency of the nose 108 can be such thatit has an added benefit of dampening a fall should the device 100 falloff a surface 110 (e.g., a table) and land on its nose 108.

Alternative Leg and Appendage Configurations

FIG. 6 shows an example device 100 that includes a pair of sideclimber-appendages 105 a and 105 b. For example, the sideclimber-appendages 105 a-105 b can be similar to the topclimber-appendage 105 shown in FIG. 1 and can serve a similar function,that of providing the device 100 with the ability to climb.Specifically, two or more side climber-appendages (e.g., sideclimber-appendages 105 a-105 b) can work with each other and/or with thelegs 104 to enable the device 100 to climb between substantiallyinclined or vertical surfaces (e.g., a slope of 45 degrees or greater),such as surfaces inside a conduit or a tube. For example, the verticalsurfaces can be spaced such that the appendage tips of the sideclimber-appendages 105 a-105 b and/or the appendage tips of the legs 104apply alternating forces on substantially opposing surfaces on which theside climber-appendages 105 a-105 b and/or the legs 104 contact.

In some implementations, the side climber-appendages 105 a-105 b canhave an upward slope (i.e., up and away from the housing 102), as shownin FIG. 6. As an example, the upward slope can allow the device 100 andits appendages to fit certain conduit geometries, e.g., including thecross-sectional tube shape of the conduit or if the conduitcross-sectional shape (e.g., a U-shape or other mostly non-rectangularshape) is not completely vertical. For example, the upward slope (asopposed to side climber-appendages 105 a and 105 b that protrudestraight out, parallel to the surface) can help to keep the device 100from flopping toward or onto its back. Moreover, the upward slope canprovide at least some force opposing the force generated by the legs 104contacting a surface.

In other words, if the conduit has a substantially round or oval crosssection, then the legs 104 of the device can contact the inside of theconduit, centered between the 7 O'clock and 5 O'clock positions, and theside climber-appendages 105 a-105 b somewhere above the 9 O'clock and 3O'clock positions. By comparison, when a single top climber-appendage105 is used, it can be substantially at the 12 O'clock position. In someimplementations, however, side climber-appendages 105 a and 105 b can besubstantially opposed, e.g., in the 9 O'clock and 3 O'clock positions.

During the vibration of the device 100, the tips of the legs 104 canapply forces to a (not necessarily level) surface (e.g., relative to theappendage tips of the legs 104). Specifically, the appendage tips,constructed from a material having a coefficient of friction to providesufficient grip during compression and sufficient hopping to enable areturn to a neutral position, can work to propel the device 100 in aforward direction (e.g., to climb up a slope inside the conduit). At thesame time, the appendage tips of the side climber-appendages 105 a-105 bcan contact surfaces that are substantially perpendicular to theappendage tips. Similarly, propulsion facilitated by an appropriatecoefficient of friction of the appendage tips of the sideclimber-appendages 105 a-105 b can further propel the device 100 in theforward direction (e.g., to climb up a slope inside the conduit). Thevarious surfaces upon which opposing appendage tips contact can besubstantially parallel to each other, e.g., the inside walls of theconduit through which the device 100 can climb.

In some implementations, grooves and/or ridges built into the inside ofthe conduit can be in alignment with the appendage tips of the sideclimber-appendages 105 a-105 b, e.g., helping to keep the device 100 inposition relative to the conduit. In some implementations, spiralpatterns can be used in the conduits so that a device 100 that entersthe conduit at one level can twist for a total of 180 degrees to flipthe device 100 onto its legs when the device 100 reaches a differentlevel. For example, the surface inside the conduit on which theappendage tips of the legs 104 contact can have a slight twist (e.g., a90 degree twist for every 90 degree arc of the conduit), andsubstantially parallel slight twists can be included for the groovesand/or ridges (or the surfaces) on which the appendage tips of the sideclimber-appendages 105 a-105 b contact.

In some implementations, the device 100 can have alternative legconfigurations. For example, legs 104 can be connected using webs thatcan serve to increase the stiffness of the legs 104 while maintaininglegs 104 that appear long. In some implementations, middle legs 104 bmay not touch the ground, which can make production tuning of the legseasier by eliminating unneeded legs from consideration. In someimplementations, devices 104 can include additional appendages that canprovide an additional life-like appearance. In some implementations, theadditional life-like appendages can resonate as the devices 100 move,and adjusting the appendages to create a desired resonance can serve toincrease randomness in motion. Additional leg configurations can providea reduced stiffness that can reduce hopping, among othercharacteristics.

In some implementations, devices 100 can include adjustment features,such as adjustable legs 104. For example, if a consumer purchases a setof devices 100 that all have the same style (e.g., an ant), the consumermay want to make some or all of the devices 100 move in varying ways. Insome implementations, the consumer can lengthen or shorten individualleg 104 by first loosening a screw (or clip) that holds the leg 104 inplace. The consumer can then slide the leg 104 up or down and retightenthe screw (or clip). For example, screws can be loosened forrepositioning legs 104, and then tightened again when the legs are inthe desired place.

In some implementations, screw-like threaded ends on leg bases 106 balong with corresponding threaded holes in the device housing 102 canprovide an adjustment mechanism for making the legs 104 longer orshorter. For example, by turning the front legs 104 a to change thevertical position of the legs bases 106 b (i.e., in the same way thatturning a screw in a threaded hole changes the position of the screw),the consumer can change the length of the front legs 104 a, thusaltering the behavior of the device 100.

In some implementations, the leg base 106 b ends of adjustable legs 104can be mounted within holes in housing 102 of the device 100. Thematerial (e.g., rubber) from which the legs are constructed along withthe size and material of the holes in the housing 102 can providesufficient friction to hold the legs 104 in position, while stillallowing the legs to be pushed or pulled through the holes to newadjusted positions.

In some implementations, in addition to using adjustable legs 104,variations in movement can be achieved by slightly changing the CG,which can serve to alter the effect of the vibration of the motor 202.This can have the effect of making the device move slower or faster, aswell as changing the device's tendency to turn. Providing the consumerwith adjustment options can allow different devices 100 to movedifferently.

Device Dimensions

FIGS. 7A and 7B show example dimensions of the device 100. For example,a length 702 is approximately 1.73 inches, a width 704 from leg tip toleg tip is approximately 0.5 inches, and a height 706 is approximately0.681 inches. A leg length 708 can be approximately 0.4 inches, and aleg diameter 710 can be approximately 0.077 inches. A radius ofcurvature (shown generally at 712) can be approximately 1.94 inches.Other dimensions can also be used. In general, the device length 702 canbe in the range from two to five times the width 704 and the height 706can be in the approximate range from one to two times the width 704. Theleg length 708 can be in the range of three to ten times the legdiameter 710. There is no physical limit to the overall size that thedevice 100 can be scaled to, as long as motor and counterweight forcesare scaled appropriately. In general, it may be beneficial to usedimensions substantially proportional to the illustrated dimensions.Such proportions may provide various benefits, including enhancing theability of the device 100 to right itself after tipping and facilitatingdesirable movement characteristics (e.g., tendency to travel in astraight line, etc.).

Construction Materials

Material selection for the legs is based on several factors that affectperformance. The materials main parameters are coefficient of friction(COF), flexibility and resilience. These parameters in combination withthe shape and length of the leg affect speed and the ability to controlthe direction of the device.

COF can be significant in controlling the direction and movement of thedevice. The COF is generally high enough to provide resistance tosideways movement (e.g., drifting or floating) while the apparatus ismoving forward. In particular, the COF of the leg tips (i.e., theportion of the legs that contact a support surface) can be sufficient tosubstantially eliminate drifting in a lateral direction (i.e.,substantially perpendicular to the direction of movement) that mightotherwise result from the vibration induced by the rotating eccentricload. The COF can also be high enough to avoid significant slipping toprovide forward movement when F_(v) is down and the legs provide aforward push. For example, as the legs bend toward the back of thedevice 100 (e.g., away from the direction of movement) due to the netdownward force on the one or more driving legs (or other legs) inducedby the rotation of the eccentric load, the COF is sufficient to preventsubstantial slipping between the leg tip and the support surface. Inanother situation, the COF can be low enough to allow the legs to slide(if contacting the ground) back to their normal position when F_(v) ispositive. For example, the COF is sufficient low that, as the net forceson the device 100 tend to cause the device to hop, the resiliency of thelegs 104 cause the legs to tend to return to a neutral position withoutinducing a sufficient force opposite the direction of movement toovercome either or both of a frictional force between one or more of theother legs (e.g., back legs 104 c) in contact with the support surfaceor momentum of the device 100 resulting from the forward movement of thedevice 100. In some instances, the one or more driving legs 104 a canleave (i.e., hop completely off) the support surface, which allows thedriving legs to return to a neutral position without generating abackward frictional force. Nonetheless, the driving legs 104 a may notleave the support surface every time the device 100 hops and/or the legs104 may begin to slide forward before the legs leave the surface. Insuch cases, the legs 104 may move forward without causing a significantbackward force that overcomes the forward momentum of the device 100.

Flexibility and resilience are generally selected to provide desired legmovement and hop. Flexibility of the leg can allow the legs to bend andcompress when F_(v) is down and the nose moves down. Resilience of thematerial can provide an ability to release the energy absorbed bybending and compression, increasing the forward movement speed. Thematerial can also avoid plastic deformation while flexing.

Rubber is an example of one type of material that can meet thesecriteria, however, other materials (e.g., other elastomers) may a havesimilar properties.

FIGS. 7C and 7D collectively show an example of a removably attachableappendage for the device 100. Some implementations of the device 100,for example, can include the top climber-appendage 105 (or some otherremovably attachable appendages). The appendages can be attached (orre-attached) as needed, such as when the device 100 is to be used inenvironments in which the device 100 can climb with the help ofclimber-appendages. Some implementations of removably attachableappendages can include a compression fitting 720 which can be fixedlyattached to the top climber-appendage 105. In some implementations, thecompression fitting 720 can include two prongs that can slide into aholed tab 722 and can snap into place using notched ends or some othermechanism(s). Referring to FIG. 7D, the top climber-appendage 105 isshown snapped into place in the holed tab 722, and the device 100 isconfigured for climbing.

FIGS. 7E and 7F show another example of a removably attachable appendagefor the device 100. For example, a removable top climber-appendageattachment 740 can include the top climber-appendage 105 that is fixedlyattached to a mounting clip 742. In some implementations, the mountingclip 742 can include two downward-projecting ends, each of which can fitinto a body notch 744 (e.g., one on each side of the device 100).Referring to FIG. 7F, the top climber-appendage attachment 740 is shownattached in place on the device 100. For example, the ends of themounting clip 742 are shown occupying the body notches 744, and thecenter portion of the mounting clip 742 straddles the width of thedevice 100. Other implementations of appendage attachments are alsopossible. For example, a snap-on shell that includes top and/or sideappendages and that engages a greater portion of the body shoulder 112of the device 100 than the mounting clip 742 can be used.

FIG. 8 shows example materials that can be used for the device 100. Inthe example implementation of the device 100 shown in FIG. 8, the legs104 are molded from rubber or another elastomer. The legs 104 can beinjection molded such that multiple legs are integrally moldedsubstantially simultaneously (e.g., as part of the same mold). The legs104 can be part of a continuous or integral piece of rubber that alsoforms the nose 108 (including nose sides 116 a and 116 b), the bodyshoulder 112, and the head side surface 114. As shown, the integralpiece of rubber extends above the body shoulder 112 and the head sidesurface 114 to regions 802, partially covering the top surface of thedevice 100. For example, the integral rubber portion of the device 100can be formed and attached (i.e., co-molded during the manufacturingprocess) over a plastic top of the device 100, exposing areas of the topthat are indicated by plastic regions 806, such that the body forms anintegrally co-molded piece. The high point 120 is formed by theuppermost plastic regions 806. One or more rubber regions 804, separatefrom the continuous rubber piece that includes the legs 104, can coverportions of the plastic regions 806. In general, the rubber regions 802and 804 can be a different color than plastic regions 806, which canprovide a visually distinct look to the device 100. In someimplementations, the patterns formed by the various regions 802-806 canform patterns that make the device look like a bug or other animateobject. In some implementations, different patterns of materials andcolors can be used to make the device 100 resemble different types ofbugs or other objects. In some implementations, a tail (e.g., made ofstring) can be attached to the back end of the device 100 to make thedevice appear to be a small rodent.

The selection of materials used (e.g., elastomer, rubber, plastic, etc.)can have a significant effect on the device's ability to self-right. Forexample, rubber legs 104 can bend inward when the device 100 is rollingduring the time it is self-righting. Moreover, rubber legs 104 can havesufficient resiliency to bend during operation of the device 100,including flexing in response to the motion of (and forces created by)the eccentric load rotated by the motor 202. Furthermore, the tips ofthe legs 104, also being made of rubber, can have a coefficient offriction that allows the driving legs (e.g., the front legs 104) to pushagainst the surface 110 without significantly slipping.

Using rubber for the nose 108 and shoulder 112 can also help the device100 to self-right. For example, a material such as rubber, having higherelasticity and resiliency than hard plastic, for example, can help thenose 108 and shoulder 112 bounce, which facilitates self-righting, byreducing resistance to rolling while the device 100 is airborne. In oneexample, if the device 100 is placed on its side while the motor 202 isrunning, and if the motor 202 and eccentric load are positioned near thenose 108, the rubber surfaces of the nose 108 and shoulder 112 can causeat least the nose of the device 100 to bounce and lead to self-rightingof the device 100.

In some implementations, the one or more rear legs 104 c can have adifferent coefficient of friction than that of the front legs 104 a. Forexample, the legs 104 in general can be made of different materials andcan be attached to the device 100 as different pieces. In someimplementations, the rear legs 104 c can be part of a single moldedrubber piece that includes all of the legs 104, and the rear legs 104 ccan be altered (e.g., dipped in a coating) to change their coefficientof friction.

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of anyinventions or of what may be claimed, but rather as descriptions offeatures specific to particular embodiments of particular inventions.Certain features that are described in this specification in the contextof separate embodiments can also be implemented in combination in asingle embodiment. Conversely, various features that are described inthe context of a single embodiment can also be implemented in multipleembodiments separately or in any suitable subcombination. Moreover,although features may be described above as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination. Other alternativeembodiments can also be implemented. For example, some implementationsof the device 100 can omit the use of rubber. Some implementations ofthe device 100 can include components (e.g., made of plastic) thatinclude glow-in-the-dark qualities so that the device 100 can be seen ina darkened room as it moves across the surface 110 (e.g., a kitchenfloor). Some implementations of the device 100 can include a light(e.g., an LED bulb) that blinks intermittently as the device 100 travelsacross the surface 110.

FIG. 10A is a flow diagram of a process 1000 for operating avibration-powered device 100 (e.g., a device that includes anyappropriate combination of the features described above). In variousembodiments, different subsets of the features described above can beincluded.

Initially, a vibration-powered device is placed on a substantially flatsurface or other surface (e.g., shaped such that multiple legs of thedevice contact the surface) at 1005. Vibration of the device is inducedat 1010 to cause forward movement. For example, vibration may be inducedusing a rotational motor (e.g., battery powered or wind up) that rotatesa counterweight. The vibration can induce movement in a directioncorresponding to an offset between the leg bases and the leg tips of oneor more driving legs (i.e., the forward direction). In particular, thisvibration can cause resilient legs to bend in one direction, at 1015, asthe net downward forces cause the device to move downward. This bending,along with using a material with a sufficiently high coefficient offriction to avoid substantial slipping, can cause the device to movegenerally forward.

As the vibration causes net upward forces (e.g., due to the vector sumof the forces induced by the rotating counterweight and the springeffect of the resilient legs) that cause the driving legs to leave thesurface or to come close to leaving the surface, the tips of the one ormore driving legs move in the forward direction (i.e., the leg deflectsin the forward direction to return to a neutral position) at 1020. Insome implementations, the one or more driving legs can leave the surfaceat varying intervals. For example, the driving legs may not leave thesurface every time the net forces are upward because the forces may notovercome a downward momentum from a previous hop. In addition, theamount of time the driving legs leave the surface may vary for differenthops (e.g., depending on the height of the hop, which in turn may dependon the degree to which the rotation of the counterweight is in phasewith the spring of the legs).

During the forward motion of the device, different drag forces on eachlateral side of the device can be generated at 1025. Generally, thesedifferent drag forces can be generated by rear legs that tend to drag(or at least that drag more than front driving legs) and alter theturning characteristics of the device (e.g., to counteract or enhanceturning tendencies). Typically, the legs can be arranged in (e.g., two)rows along each lateral side of the device, such that one or more of thelegs in one row drag more than corresponding legs in another row.Different techniques for causing the device to generate these differentdrag forces are described above.

If the device overturns, rolling of the device is induced at 1030. Ingeneral, this rolling tendency can be induced by the rotation of thecounterweight and causes the device to tend to independently rightitself. As discussed above, the outer shape of the device along thelongitudinal dimension (e.g., substantially parallel to the axis ofrotation and/or the general forward direction of movement of the device)can be shaped to promote rolling (e.g., by emulating longitudinal“roundness”). Rolling of the device can also be stopped by a relativelywide spread between the rows of legs at 1035. In particular, if the legsare wide enough relative to the COG of the device, the rotational forcesgenerated by the rotating counterweight are generally insufficient(absent additional forces) to cause the device to roll over from theupright position.

At 1040, resiliency of the nose of the device can induce a bounce whenthe device encounters an obstacle (e.g., a wall). This tendency tobounce can facilitate changing directions to turn away from an obstacleor toward a higher angle of incidence, particularly when combined with apointed shaped nose as discussed above. The resilient nose can beconstructed from a elastomeric material and can be integrally moldedalong with lateral shoulders and/or legs using the same elastomericmaterial. Finally, lateral drifting can be suppressed at 1045 based on asufficiently high coefficient of friction at the leg tips, which canprevent the legs from tending to slide laterally as the rotatingcounterweight generates lateral forces.

FIG. 10B is a flow diagram of a process 1050 for the vibration-powereddevice 100 to climb. For example, the device 100 can include anyappropriate combination of the features described above (e.g.,appendages that contact substantially opposing surfaces). In variousembodiments, different subsets of the features described above can beincluded. The process 1050 can be used in combination with the process1000 (See FIG. 10A), for example, when the device 100 operates andtransitions between substantially flat areas that can facilitate randommotion to other areas that include conduits or other apparatus in whichthe device 100 can climb.

Initially, a vibration-powered device is introduced to a substantiallyinclined (and at least partially enclosed) conduit at 1055. As anexample, the conduit can be the conduit 901 shown in FIG. 9A. The device100 can enter the conduit 901, for example, after the device completesits travel through the connecting pathway 906. In another example, theconduit can be the conduit loop 950 shown in FIG. 9C, and the device 100can enter the loop conduit 950 at the entrance 952. Otherimplementations can use conduits that have other shapes.

Vibration of the device is induced to alternately cause movement towardeach of two or more appendages disposed in different directions at 1060.For example, as the device 100 enters the conduit (e.g., the conduit 901or the loop conduit 950), vibration induced by the rotating eccentricload alternately causes movement in the direction of the legs 104 andthe top climber-appendage 105 (or the side climber-appendages 105 a-105b). The appendages of the device 100 are disposed in differentdirections because the legs 104 project generally downward from thedevice 100, and the top climber-appendage 105 (or sideclimber-appendages 105 a-105 b) projects upward (or substantiallysideways) relative to the device 100.

The vibration provides substantially opposing forces on the appendagesat 1065. Each opposing force is in a direction that is substantiallyorthogonal to the forward direction. For example, the vibration resultsin an orthogonal leg force that causes the legs 104 to contact andcompress against the surface of the conduit, such as the floor surfaceof the conduit 901. As the vibration (and resilient forces of the legs104) subsequently cause the device 100 to move in the oppositedirection, the vibration results in an orthogonal climber-appendageforce that causes the top climber-appendage 105 to contact and compressagainst the ceiling surface with an opposing force. The alternating andopposing forces can occur in rapid succession and are generallyorthogonal to the direction of movement of the device (e.g., thedirection of movement through the conduit 901 or the loop conduit 950).

The device is deflected in the forward direction using resistance tomovement by the appendages in the backward direction at 1070. Forexample, in addition to the orthogonal forces induced by the rotatingeccentric load, additional force components provide forward movement ofthe device. In particular, the tips of the legs 104 and the topclimber-appendage 105 (or side climber-appendages 105 a-105 b) havecoefficients of friction that allow the tips to “grip” the surfaces ofthe conduit to prevent the device 100 from sliding backward.

The device is caused to climb using the opposing forces and thedeflection of the appendages at 1075. For example, the alternating gripby the legs 104 and the climber-appendage(s) allows the device 100 tohave a ratcheting motion between the parallel surfaces of the conduit,resulting in the device 100 climbing the conduit.

FIG. 11 is a flow diagram of a process 1100 for constructing avibration-powered device 100 (e.g., a device that includes anyappropriate combination of the features described above). Initially, thedevice undercarriage is molded at 1105. The device undercarriage can bethe underside 122 shown in FIG. 1 and can be constructed from a hardplastic or other relatively hard or stiff material, although the type ofmaterial used for the underside is generally not particularly criticalto the operation of the device. An upper shell is also molded at 1110.The upper shell can include a relatively hard portion of the upper bodyportion of the housing 102 shown in FIG. 1, including the high point120.

The upper shell is co-molded with an elastomeric body at 1115 to formthe device upper body. The elastomeric body can include a singleintegrally formed piece that includes appendages (e.g., legs 104),shoulders 112, and nose 108. Co-molding a hard upper shell and a moreresilient elastomeric body can provide better constructability (e.g.,the hard portion can make it easier to attach to the deviceundercarriage using screws or posts), provide more longitudinalstiffness, can facilitate self-righting (as explained above), and canprovide legs that facilitate hopping, forward movement, and turningadjustments. In some implementations, the appendages that are integrallymolded with the resilient elastomeric body can include one or more topclimber-appendages 105 and/or two or more side climber-appendages (e.g.,the side climber-appendages 105 a and 105 b), or combinations thereof.In implementations in which appendages such as the climber-appendages105, 105 a and 105 b can be removably attached, the body can be moldedto include the holed tab 722, the body notches 744, or other featuresuseful for attaching appendages.

The housing is assembled at 1120. The housing generally includes abattery, a switch, a rotational motor, and an eccentric load, which mayall be enclosed between the device undercarriage and the upper body.

Habitats

FIG. 12A shows an example tube habitat 1200 in which multiple devices100 can operate and interact. In this example, the tube habitat 1200includes three arenas 1202 a-1202 c, each of which can be hexagonallyshaped as shown. As shown in FIG. 12A, the arenas 1202 a-1202 c are atthree different elevations and are substantially level and parallel toeach other, but other configurations are possible. The arena 1202 a isthe topmost of the three arenas, with the arena 1202 c at the bottom andthe arena 1202 b substantially in the middle.

The arenas 1202 a-1202 c are connected with tube assemblies 1204 a-1204e of various lengths, shapes, and configurations. For example, the tubeassemblies 1204 a and 1204 c each connect the arena 1202 a to the arena1202 c. Similarly, the tube assemblies 1204 b and 1204 d each connectthe arena 1202 a to the arena 1202 b. Finally, the tube assembly 1204 econnects the arena 1202 c to itself by way of a loop in the tubeassembly 1204 e that passes over the top of the arena 1202 b.Connections between arenas 1202 a-1202 c and tube assemblies 1204 a-1204e are made at gate openings along the sides of the arenas 1202 a-1202 c.Closed gates, where the tube assemblies 1204 a-e are not connected tothe arenas 1202 a-1202 c, can prevent the devices 100 from exiting thetube habitat 1200 during operation. In some implementations, the tubeassemblies 1204 a-e can be assembled using tube components andconnectors described below with reference to FIGS. 13A-13W and 14A-14H.Other configurations of tube assemblies are possible, including tubeassemblies of a solid piece and/or tube assemblies that use componentsnot described in FIGS. 13A-13W and 14A-14H.

FIG. 12B shows a top view of the tube habitat 1200. This view moreclearly shows both lateral sides of the tube assembly 1204 e. Gates 1208are shown in an open state.

Various connectors can be used to connect the components of the tubehabitat 1200. For example, one type of connector 1206 a (e.g., refer toFIGS. 14E-H) can connect any one of various types of tubes to any of thearenas 1202 a-1202 c. A second type of connector 1206 b (e.g., refer toFIGS. 14A-D) can connect a pair of tubes.

FIGS. 13A through 13D show various views of an example straight tubeassembly 1300. Specifically, FIG. 13A is a top view, FIG. 13B is aperspective view, FIG. 13C is a side view, and FIG. 13D is a front view.The FIGS. 13B and 13D show an opening 1302 through which the device 100can travel, e.g., through the length of the straight tube assembly 1300.In some implementations, the straight tube assembly 1300 can be wideenough such that two lanes exist, allowing two devices 100 to pass. Thelanes are not formal lanes or defined lanes as such, but the opening1302 has a width that is equal to or more than double the width of thedevice 100 (at its widest point). In fact, two devices 100 can meetessentially head-on inside the straight tube assembly 1300 (and othertube assemblies described in this document), and the two devices 100 canresolve their meeting, deflect off each other, and continue on.

In some implementations, the straight tube assembly 1300 can includeridges 1304 (or other features) which can facilitate proper positioningof connectors. For example, the connectors, as described in detailbelow, can connect the straight tube assembly 1300 to another tubeassembly or to another component used in a habitat for the device 100(e.g., the tube habitat 1200). In some implementations, connectors canengage with the ridges 1304, such as by fitting over the top of theassembly 1300 and abutting the ridge 1304. Thus, the ridges 1304 arestopping points, e.g., providing a stop for a connector that slides ontothe end of the straight tube assembly 1300.

In some implementations, the straight tube assembly 1300 is manufacturedfrom two pieces (e.g., substantially two halves) that are joined atseams 1306. In some implementations, the straight tube assembly 1300 ismanufactured as a single piece.

FIGS. 13E through 13G show example dimensions of the straight tubeassembly 1300. Dimensions of the device 100 are also shown, as thosedimensions are related to the dimensions of the straight tube assembly1300. FIGS. 13E through 13G show top, side and front views,respectively, of the device 100 with its back end inside the straighttube assembly 1300.

Referring to FIG. 13E, a nose-to-climber-appendage distance 1310 (e.g.,15 mm) defines the distance from the nose 108 to the front of theclimber-appendage 105. Referring to FIG. 13F, a climber-appendageelevation 1312 (e.g., 22 mm) defines the elevation of the top of theclimber-appendage 105 relative to the bottoms of the legs 104. Referringto FIG. 13G, a tube width 1314 (e.g., 30 mm) and a tube height 1316(e.g., 20 mm) define the inside width and height, respectively, of thestraight tube assembly 1300. In some implementations, the tube width1314 and the tube height 1316 can be used in other components, e.g.,other straight tube assemblies (e.g., of different lengths), curvedassemblies, and/or assemblies of other shapes or configurations. A legoffset dimension 1318 (e.g., 14 mm) is included here to show therelative width of the device 100 at its widest point, e.g., the outeredges of its legs 104. For example, because the example leg offsetdimension 1318 of 14 mm is less than half of the example tube width 1314of 30 mm, ample horizontal space exists in the straight tube assembly1300 for two devices 100 to pass.

FIGS. 13H through 13K show various views of an example curved tubeassembly 1322. Specifically, FIG. 13H is a side view, FIG. 13I is a backview, FIG. 13J is a bottom view, and FIG. 13K is a perspective view.Referring to FIG. 13H, the device 100 can enter the curved tube assembly1322 through a front opening 1324 at the front of the curved tubeassembly 1322. FIG. 13K shows an opening 1326 from which the device 100can exit the curved tube assembly 1322 after entering at the frontopening 1324 and climbing through the tube. Devices 100 can travel ineither direction through the curved tube assembly 1322.

The curved tube assembly 1322 can have the same or similar insidedimensions as the straight tube assembly 1300 (e.g., a width of 30 mmand a height of 20 mm). As a result, when the curved tube assembly 1322is connected to other components such as the straight tube assembly1300, the device 100 can expect a substantially smooth transition at theconnection points. Further, the curved tube assembly 1322 is wide enoughfor two devices 100 to pass.

In some implementations, the curved tube assembly 1322 can includeridges 1328 (or other features), which can facilitate a snap-togetherfitting with connectors. For example, the connectors, as described indetail below, can connect the curved tube assembly 1322 to another tubeassembly or to another component used in a habitat for the device 100(e.g., the tube habitat 1200).

FIGS. 13L through 13Q show various views of an example Y-shaped tubeassembly 1334. Specifically, FIG. 13L is a side view, FIG. 13M is afront view, FIG. 13N is a perspective view, FIG. 13O is a bottom view,FIG. 13P is a cut-away side view, and FIG. 13Q is a cut-away perspectiveview.

The Y-shaped tube assembly 1334 includes a flap 1336 at the intersectionof a straight section 1338 and a curved section 1340. The flap 1336 cancontrol the direction of movement by devices 100 inside the Y-shapedtube assembly 1334. Referring to FIGS. 13P and 13Q, the flap 1336 isshown closed, e.g., hanging in a downward position, substantiallyparallel to the straight section 1338. When the flap 1336 is closed,devices 100 can travel straight downward or upward through the straightsection 1338, and a device 100 traveling upward cannot enter the curvedsection 1340. The flap 1336 hangs downward from its connection point ona pivot pin 1342, upon which the flap 1336 can pivot.

When flap 1336 is closed, a device 100 traveling downward through thecurved section 1340 can open the flap 1336. The nose 108 or other partsof the device 100 can push the flap 1336 open. At that time, the bottomof the flap 1336 can contact the straight section 1338 substantiallynear a position 1344 on the straight section 1338. The bottom of thecurved section 1340 is shaped in such a way that, when the flap 1336 isopen and extends to the position 1344, the distance between the flap1336 and a substantially parallel portion of the curved section 1340 issubstantially uniform (e.g., about 20 mm). This distance is consistentwith the interior height (e.g., 20 mm) of the remainder of the Y-shapedtube assembly 1334, which allows the device 100 to stay in contactsubstantially continuously with the surfaces of the Y-shaped tubeassembly 1334. In this way, forward progress of the device 100 isessentially continuous, though not necessarily at a constant speed.

In some implementations, after one or more devices 100 engage and thenpass through the flap 1336, gravity can cause the flap 1336 to return toits closed or downward position. In some implementations, during theshort period of time that the flap 1336 is open, a device 100 travelingupward through the straight section 1338 can enter the curved section1340.

FIGS. 13R through 13W show various views of an example loop tubeassembly 1350. Specifically, FIG. 13R is a side view, FIG. 13S is afront view, FIG. 13T is a perspective view, FIG. 13U is a bottom view,FIG. 13V is a cut-away side view, and FIG. 13W is a cut-away perspectiveview. In this example, the loop tube assembly 1350 provides aloop-the-loop feature. For example, a device 100 entering either end(e.g., opening 1352) will complete the loop and exit the opposite end(e.g., opening 1354).

The loop tube assembly 1350 includes flaps 1356 and 1358 that allow theloop tube assembly 1350 to be bi-directional. A linkage section 1360attached to the flaps 1356 and 1358 causes the flaps 1356 and 1358 tomove substantially in unison, e.g., movement of one in reaction to themovement of the other. In some implementations, the linkage section 1360can include multiple (e.g., three) inter-connected, hinged levers. Forexample, when a device 100 enters the loop tube assembly 1350 at theopening 1352 and pushes the flap 1356 upward (if not already up), thelinkage section 1360 causes the flap 1358 to drop. The flap 1358 thusdiverts the device 100 into the circular part of the loop tube assembly1350. Then when the device 100 has nearly completely navigated thecircular part, the device 100 contacts and pushes down the flap 1356.Simultaneously, the attached linkage section 1360 causes the flap 1358to rise, allowing the device 100 to pass beneath the flap 1358 and toexit the loop tube assembly 1350 at the opening 1354. A similar sequenceof events occurs if the device 100 enters the loop tube assembly 1350through the opening 1354.

In some implementations, a user can use the linkage section 1360 and/orother controls to control the operation of the flaps 1356 and 1358. Inthis way, the user can control the direction of movement of devices 100inside the loop tube assembly 1350. For example, user-controllable knobsor other controls can be attached to the linkage section 1360.

In some implementations, the linkage section 1360 can include attachedarms that are substantially perpendicular to the levers of the linkagesection 1360. The arms can fit through slots 1362 to engage the flaps1356 and 1358, e.g., along the undersides of the flaps 1356 and 1358.

In some implementations, two devices 100, traveling in oppositedirections, can be inside the loop tube assembly 1350 at the same time.If the two devices 100 are in the circular part, for example, whicheverdevice 100 reaches its respective flap 1356 or 1358 first will be thefirst to exit the loop tube assembly 1350. In some situations, a device100 may be temporarily delayed at either of the flaps 1356 or 1358 whilethe other device 100 passes underneath in the opposite direction.

FIGS. 14A through 14D show various views of an example connector 1400.Specifically, FIG. 14A is a top view, FIG. 14B is a perspective view,FIG. 14C is a front view, and FIG. 14D is a side view. The connector1400 can be used to connect a pair of tubes such as any two combinationsof the tubes 1300, 1322, 1334 and 1350 described above with reference toFIGS. 13A-13W. The connector 1400 includes sections 1402 a, 1402 b and1404. Sections 1402 a and 1042 b are identical, making the connector1400 symmetrical and interchangeable, allowing either section 1402 a or1402 b to be attached to any of the tubes 1300, 1322, 1334 and 1350. Thesection 1404 has the same height and width dimensions as the tubes 1300,1322, 1334 and 1350. In some implementations, the connector 1400 can beused as the connector 1206 b described above with reference to FIGS. 12Aand 12B. Other types of connectors can be used in other implementations.

FIGS. 14E through 14H show various views of another example connector1410. Specifically, FIG. 14E is a top view, FIG. 14F is a perspectiveview, FIG. 14G is a front view, and FIG. 14H is a side view. Theconnector 1410 can be used to connect an arena (e.g., one of the arenas1202 a-c) to any of the tubes 1300, 1322, 1334 and 1350 described abovewith reference to FIGS. 13A-13W. The connector 1410 can also be used toconnect a tube to other types of components having a locking tabconnection 1412.

Thus, particular embodiments of the subject matter have been described.Other embodiments are within the scope of the following claims.

What is claimed is:
 1. An apparatus comprising: a body; a vibratingmechanism coupled to the body; and a plurality of appendages each havingan appendage base proximal to the body and an appendage tip distal tothe body, wherein: at least a portion of the plurality of appendages areadapted to cause the apparatus to move across a surface in a forwarddirection generally defined by a longitudinal offset between theappendage base and the appendage tip as the vibrating mechanism causesthe apparatus to vibrate; and the plurality of appendages include two ormore appendages constructed from a resilient material, wherein theappendage tips of the two or more appendages project outwardly from thebody such that the two or more appendages are adapted to contactopposing surfaces to apply at least partially opposing forces on theopposing surfaces and to produce a net force in a direction generallydefined by a longitudinal offset between the appendage base and theappendage tip of the two or more appendages as the vibrating mechanismcauses the apparatus to vibrate.
 2. The apparatus of claim 1 wherein thetwo or more appendages are adapted to contact opposing surfaces that aresubstantially parallel to one another.
 3. The apparatus of claim 1wherein the two or more appendages are adapted to contact at least twoopposing surfaces disposed on an at least substantially enclosedconduit.
 4. The apparatus of claim 1 wherein the net force in adirection generally defined by an offset between the appendage base andthe appendage tip of the two or more appendages exceeds an opposinggravitational force on the apparatus.
 5. The apparatus of claim 1wherein each of the two or more appendages, as a result of contact witha corresponding surface, produce a net force that includes a positivecomponent force in a direction substantially perpendicular to thecorresponding surface and a positive component force in a directiongenerally defined by a longitudinal offset between the appendage baseand the appendage tip.
 6. The apparatus of claim 5 wherein the positivecomponent force in the direction substantially perpendicular to thecorresponding surface for one of the two or more appendages issubstantially opposed to the positive component force in the directionsubstantially perpendicular to the corresponding surface for at leastone other appendage of the two or more appendages.
 7. The apparatus ofclaim 1 wherein the plurality of appendages include a plurality of legsgenerally disposed in a first direction and the two or more appendagesinclude a first appendage generally disposed in a second directionsubstantially opposite the first direction.
 8. The apparatus of claim 7wherein the two or more appendages further include at least two legs ofthe plurality of legs, and the at least two legs and the first appendageare adapted to enable the apparatus to climb between substantiallyvertical surfaces that are spaced such that the appendage tips of the atleast two legs and the appendage tip of the first appendage applyalternating forces on the opposing surfaces.
 9. The apparatus of claim 7wherein the legs are arranged in two rows, with the appendage base ofthe legs in each row coupled to the body substantially along a lateraledge of the body.
 10. The apparatus of claim 1 wherein at least one ofthe two or more appendages is removably attached to the body.
 11. Theapparatus of claim 1 wherein the plurality of appendages include aplurality of legs generally disposed in a first direction and the two ormore appendages include: a first appendage generally disposed in asecond direction substantially perpendicular to the first direction; anda second appendage generally disposed in a third direction substantiallyperpendicular to the first direction and substantially opposite thesecond direction.
 12. The apparatus of claim 1 wherein the vibratingmechanism includes a rotational motor that rotates an eccentric load.13. The apparatus of claim 1 wherein at least one of the two or moreappendages are forward of a longitudinal center of gravity of theapparatus.
 14. The apparatus of claim 1 wherein each of the plurality ofappendages are: constructed from a flexible material; injection molded;and integrally coupled to the body at the appendage base.
 15. Theapparatus of claim 1 wherein forces from rotation of the eccentric loadinteract with a resilient characteristic of at least one drivingappendage to cause the at least one driving appendage to leave a supportsurface as the apparatus translates in the forward direction.
 16. Theapparatus of claim 1 wherein a coefficient of friction of a portion ofat least a subset of the legs that contact a support surface issufficient to substantially eliminate drifting in a lateral direction.17. The apparatus of claim 1 wherein the eccentric load is configured tobe located toward a front end of the apparatus relative to drivingappendages, wherein the front end of the apparatus is defined by an endin a direction that the apparatus primarily tends to move as therotational motor rotates the eccentric load.
 18. The apparatus of claim1 wherein the plurality of appendages are integrally molded with atleast a portion of the body.
 19. The apparatus of claim 1 wherein atleast a subset of the plurality of appendages, including the two or moreappendages, are curved, and a ratio of a radius of curvature of thecurved appendages to appendage length of the appendages is in a range of2.5 to
 20. 20-25. (canceled)
 26. An apparatus comprising: a body; avibrating mechanism coupled to the body; and a plurality of resilientappendages each having an appendage base proximal to the body and anappendage tip distal to the body, wherein at least a subset of theplurality of appendages extend outwardly from the body, are disposedsuch that each of the appendages in the subset are adapted to contactone of a plurality of substantially parallel surfaces, and are adaptedto cause the apparatus to climb up a substantially inclined surface asvibration induced by the vibrating mechanism causes appendages in thesubset to at least alternately contact one of a plurality ofsubstantially parallel facing surfaces.
 27. The apparatus of claim 26wherein each of the appendages in the subset are: curved in a directionsubstantially opposite the forward direction; and constructed from anelastomeric material. 28-30. (canceled)
 31. The apparatus of claim 26wherein each of the plurality of resilient appendages, as a result ofcontact with a corresponding surface, produce a net force that includesa positive component force in a direction substantially perpendicular tothe corresponding surface and a positive component force in a directiongenerally defined by a longitudinal offset between the appendage baseand the appendage tip.
 32. The apparatus of claim 31 wherein thepositive component force in the direction substantially perpendicular tothe corresponding surface for one of the resilient appendages issubstantially opposed to the positive component force in the directionsubstantially perpendicular to the corresponding surface for at leastone other appendage of the plurality of appendages.
 33. An apparatuscomprising: a body; a vibrating mechanism coupled to the body; and aplurality of resilient appendages each having an appendage base proximalto the body and an appendage tip distal to the body, wherein at least asubset of the plurality of appendages extend outwardly from the body,are disposed such that each of the appendages in the subset isconfigured to contact one of a plurality of substantially opposingsurfaces, and are configured to cause the apparatus to climb between thesubstantially opposing surfaces in substantially an inclined directionas vibration induced by the vibrating mechanism causes appendages in thesubset to at least alternately contact one of a plurality ofsubstantially opposing surfaces.
 34. The apparatus of claim 33 wherein:the plurality of resilient appendages includes a plurality of legs eachhaving a leg base and a leg tip at a distal end relative to the legbase; the legs are coupled to the body at the leg base and include atleast one elastomeric driving leg; the vibration causes the device tomove in a forward direction generally defined by an offset between theleg base and the leg tip of the at least one driving leg as the devicevibrates; at least one of the appendages in the subset includes one ofthe plurality of legs; and at least one of the plurality of resilientappendages is attached to a top side of the body.
 35. The apparatus ofclaim 33 wherein the subset of appendages includes at least threeappendages.
 36. The apparatus of claim 33 wherein the subset ofappendages are configured to contact substantially opposing surfacesdisposed in a vertical conduit.
 37. The apparatus of claim 36 wherein:each of the subset of appendages is configured to repeatedly contact aninternal surface of the conduit for sufficient periods to producegenerally forward motion; the device is configured such that vibrationof the device causes at least one of the subset of resilient appendagesto deflect in a direction opposite the forward direction withoutsubstantial slipping of the at least one resilient appendage on acorresponding internal surface of the conduit when net forces on the atleast one appendage are toward the corresponding internal surface; andresiliency of the at least one appendage is configured to cause the atleast one appendage to deflect in the forward direction when net forceson the at least one appendage are away from the corresponding internalsurface.
 38. The apparatus of claim 33 wherein the subset of appendagesare configured to contact substantially opposing surfaces disposed in acurved tube.
 39. The apparatus of claim 33 wherein the subset ofappendages are configured to contact substantially opposing surfacesdisposed in a tube having parallel internal surfaces.